Pre Barbarossa direction for German Tanks?

[spaceviking]

I am curious if there is any information on the direction that German tanks and armoured vehicles were heading prior to the invasion of the Soviet Union. Tanks such as the Tiger and Panther (among others) are described as being designed in response to the surprising effectiveness of the T-34 and KV designs. Had the Germans say postponed Barbarossa for 2-3 years (and assuming Soviets are not aggressive) would German tank design have taken a radically different course?

[Bottlestein]

^ Weren't the designs more or less limited by their manufacturing ability? Germany could not really produce much more powerful engines - they simply did not have enough stockpiles of the right grade steel to make production versions of stronger pistons. In the absence of better engines or transmission - you are limited to tweaking guns and armor.

Actually, who would they want to fight if they postpone Barbarossa? That will pretty much determine what sort of tank they make.

[xt828]

Wasn't the Tiger a pre-Barbarossa design? IIRC design work started prior to the invasion, and built upon previous heavy tanks which had not progressed beyond prototype. The Germans had been quite dismayed by the Matilda IIs in France, which were nigh-invulnerable to anything short of an 88 hit, and quite a few of the French designs were similarly difficult to kill, so it's not illogical for them to begin development of a tank which would be able to defeat those tanks.

Aside from that, all I can think of are the abortive Neubaufahrzeug and Durchbruckwagen designs, though I do remember reading once about a tank derived from the same school of design as the earlier panzers, armed similarly to the IV but with heavier armour, though I can't track it down now.

[Zinegata]

Well, there'd be a lot fewer of those weird mismash tank destroyers (i.e. Marders). Very many German designs were honestly stop-gap machines that were rushed into production to counter the appearance of Allied tanks like the T-34.

Two tanks would probably remain quite prominent in any scenario however: The Mark III and the Mark IV. Both designs had provisions for gun upgrades (50mm gun for the Mk III, a bigger 75mm for the MK IV), which extended their service lives and made them better value for money than say, the Mk II.

[DarkArk]

The Tiger was a pre-Barbarossa design as I recall. Notice the Tiger does not have any significant sloped armor, not that it really matters since it is so thick to begin with.

The design of the Panther was a direct result of encounters with the T-34, which outclassed anything the Germans had in 1941. At first German designers wanted to just directly copy the T-34, but Hitler wouldn't let them. Kursk might have turned out differently if the T-34 lookalike wasn't having massive teething problems.

The Germans probably would have ended up with more tanks like the Tiger, and probably would only have figured out sloped armor if on a fluke, or if they started to look more seriously at Soviet tank design. If Guderian still had sway among German high command the Germans might well have never even seriously developed heavy armor, and continued to refine a Pz. 4-style chassis into a faster and more mobile armor, rather than brute force heavy armor.

[Sea Skimmer]

The Tiger was a pre-Barbarossa design as I recall. Notice the Tiger does not have any significant sloped armor, not that it really matters since it is so thick to begin with.

It was pre Barabrossa and based on work that went back before the start of the war, which is why it didn't break down quite so much as the Panther and Tiger II. Had more time to mature on the drawing board.

[Marcus Aurelius]

The Tiger was a pre-Barbarossa design as I recall. Notice the Tiger does not have any significant sloped armor, not that it really matters since it is so thick to begin with.

It was pre Barabrossa and based on work that went back before the start of the war, which is why it didn't break down quite so much as the Panther and Tiger II. Had more time to mature on the drawing board.

Yes. The breakthrough tank was in the late 1930 a common concept and you could say that the first (semi-)successful implementation was the French B1bis. The Tiger was actually superior to the KV-1 in most respects, including even reliability(!), but the latter was fielded first and achieved some remarkable things tactically in 1941 (although in most cases they had no wider significance), so when people think about an early WW2 heavy tank, the KV-1 is the one that comes to mind the most.

The sloped armor issue is sometimes overplayed; sloped armor has certain advantages but it's not better than vertical armor in all respects. The British managed to make quite good tanks without much in the way of sloped armor even during the second half of the war, including the Churchill VII, the Comet and even the post-war Centurion, which has only a sloped glacis and that's about it.

The really interesting part of this speculation is whether the Germans would have replaced the Pz III with the Pz IV as the main medium tank without the influence of the T-34. I think it would have at least happened later after encountering the M3 and M4 Mediums in North Africa, because apparently they believed that the long 50 mm armed Pz III was good enough until encountering the T-34. I can understand why they thought so, since the Pz III was mechanically the most reliable of German medium or heavy tanks. The Ausführung L and later actually had as much armor as the later Pz IV variants while still presenting a smaller target profile.

[Sea Skimmer]

The M3 and M4 would have certainly pushed up gun caliber. They had armor to resist the long 50mm and enough HE capability to shoot towed 50mm guns out of action. Without the KV-1 around though the German use of 88mm anti tank guns in all forms might be reduced.

[xt828]

The Germans used 88s in a direct fire capacity from quite early on, notably in France where they were the best option for engaging Matilda, Char B1bis and Somua S35 tanks, all of which were a struggle for smaller German weapons to deal with. The main difference between France and the USSR in this regard was that the French tanks were not especially plentiful, and the German victory was remarkably quick - France fell faster than Poland, after all. The Soviets, on the other hand, not only held on but churned out T-34s and KVs in substantial numbers - they were not rare tanks.

The British had an unfortunate trend towards having either excellent armour or adequate armament, but not both, until well into the midwar period. Remember that the M3 Medium Lee/Grant was welcomed by British tanks due to the increased power of its main gun over the contemporary British tanks, even though it was in a sponson. Without Barbarossa, and with the British as the main opposition, I think you'd still see the deployment of the Tiger, though it may be held back a bit to ensure there are not wrinkles, and the ongoing up-gunning and up-armouring of the Pz3 and 4. It might also be interesting to look at the Italian Sahariano tank design, just in terms of what the other North African combatant though was a good idea - a cruiser-style tank.

[Sea Skimmer]

The 88mm Flak 18 was used for direct fire in Spain and was always intended for the role, which is why it had on mount depression unlike almost all other heavy AA guns. But the point being that it proliferated heavily as a dedicated anti tank weapon and with units as large as battalions doing nothing else, not just flak units pressed into ground service from time to time. Without heavy armor showing up in 1941 less of this would happen.

[Marcus Aurelius]

The Germans used 88s in a direct fire capacity from quite early on, notably in France where they were the best option for engaging Matilda, Char B1bis and Somua S35 tanks, all of which were a struggle for smaller German weapons to deal with. The main difference between France and the USSR in this regard was that the French tanks were not especially plentiful, and the German victory was remarkably quick - France fell faster than Poland, after all. The Soviets, on the other hand, not only held on but churned out T-34s and KVs in substantial numbers - they were not rare tanks.

Production-wise the B1bis and the S35 were not really that rare. There were 369 B1bis'es and 430 S35s made, which is in the same ballpark as KV-1s and T-34s during the Barbarossa, and even more so considering that the Eastern Front was much longer. However, I have no figures on how many of those were actually used in combat against Germans. Due to logistical difficulties and the ongoing reorganization of the French armored units in May 1940 many were probably not deployed at all or were lost to mechanical breakdowns. Still, both the KV-1 and T-34 were relatively rare in 1941. The first major deployment of the T-34 was the Soviet counter-offensive in December 1941. However, even in that offensive most tanks were still older T-26 and BT models with a good measure of newly manufactured T-40 light tanks, and T-60s during the later stages of the Winter counter-offensive.

[CaptHawkeye]

The Germans were no strangers to fighting decent numbers of qualitatively superior enemy armour during the Invasion of the France. Even during the initial stages of Barbarossa the OKW reported that encounters with T-34s and KV-1s were rare and were not a problem. This attitude made a 180 by the time winter rolled around and suddenly the T-34 and KV-1 were winning the war for the Russians. It seems to me that the Wehrmacht was just frustrated with the lack of progress it was making during the later stages of Barbarossa and German commanders needed to pin the blame on something. After all everybody in Germany predicted the combination of corrupt leadership in the Kremlin and the racial inferiority of the slavs would lead to the Soviet Union caving in on itself. So it came as a real shock when winter rolled around and the Hammer and Sickle were still flying over the Kremlin.

I'm sure if the Invasion of France ended up slowing down we would have heard more about how "amazing" those Somuas and Matilda IIs were.

[Slacker]

Agreed. Even the Polish 7TP was a decent tank-reports were that the 37mm it mounted was more than powerful enough to deal with anything in the German inventory up to the PIV. The issue was that there weren't enough of them to stop the Germans and they weren't used properly. Doctrine won the early war for the Germans just as surely as it won the late war for the Allies.

[montypython]

I'd think something like this would be the ultimate direction of the Panzer forces without Barbarossa:



Just add Panzer III-style torsion bars and that would be just right...

[Marcus Aurelius]

Agreed. Even the Polish 7TP was a decent tank-reports were that the 37mm it mounted was more than powerful enough to deal with anything in the German inventory up to the PIV.

The 7TP was a development of the Vickers 6-ton tank just like the T-26. The 7TP had a bit more armor and better build quality (i.e. it was more reliable), the T-26 had a better gun (Excluding the M1931, which was a direct copy of the original 6-ton tank and had machine gun only armament. It was only used in Winter War anyways.) A big factor why the 7TP did so well was that in 1939 the Pz I and Pz II still made a very large percentage of the German tank forces, whereas in 1941 there were many more Pz III and of course Pz 38(t) tanks, the importance of which for the early German victories is often forgotten.

[Big Orange]

A big factor why the 7TP did so well was that in 1939 the Pz I and Pz II still made a very large percentage of the German tank forces, whereas in 1941 there were many more Pz III and of course Pz 38(t) tanks, the importance of which for the early German victories is often forgotten.

In May 1940 there were Panzer divisions heavily dominated by Czech made Panzerkampfwagen, with most zug formations in the 10th, 11th, and 25th Panzer regiments comprised almost entirely of the Skoda LT-35 and Skoda LT-38 tanks. In Dunkirk even the older, smaller Panzer 35 model performed surprisingly well against British two pounder AT cannons. They were outliving their usefulness as frontline tanks by late 1941 though and by mid 1942 were rendered obsolete by the Panzer IIIs upgunned with the 5cm KwK39 L/60 cannon and Panzer IVs upgunned with the 7.5cm KwK44 L/43 cannon (that could more feasibly penetrate KV-1 grade armour).

And while the BEF was much more heavily motorised than either the French and Germans, with the French had flashy heavy tanks like the Char B1, the Germans won because they formed up their tanks (poor or average by themselves) into huge spear formations that advanced as quickly as possible to the French and Belgium coast, cutting up the French, Belgium, and British forces from each other. And I wouldn't overstate the relative inferiority of German armour when in the Arras counter attack alone 43 out of 88 British tanks were destroyed (half by artillery), with only 28 surving tanks limping back, and the rest presumably lost to breakdowns or terrain.

The Somua 35 was as roughly well balanced as the Panzer 38(t), III and IV with somewhat better armour and protection, with a better layout than the very awkward looking Char B1bis, it still had its commander-cum-gunner cooped up in its cramped single turret, with the interior Panzer crew space better laid out.

[Marcus Aurelius]

In May 1940 there were Panzer divisions heavily dominated by Czech made Panzerkampfwagen, with most zug formations in the 10th, 11th, and 25th Panzer regiments comprised almost entirely of the Skoda LT-35 and Skoda LT-38 tanks. In Dunkirk even the older, smaller Panzer 35 model performed surprisingly well against British two pounder AT cannons. They were outliving their usefulness as frontline tanks by late 1941 though and by mid 1942 were rendered obsolete by the Panzer IIIs upgunned with the 5cm KwK39 L/60 cannon and Panzer IVs upgunned with the 7.5cm KwK44 L/43 cannon (that could more feasibly penetrate KV-1 grade armour).

And while the BEF was much more heavily motorised than either the French and Germans, with the French had flashy heavy tanks like the Char B1, the Germans won because they formed up their tanks (poor or average by themselves) into huge spear formations that advanced as quickly as possible to the French and Belgium coast, cutting up the French, Belgium, and British forces from each other. And I wouldn't overstate the relative inferiority of German armour when in the Arras counter attack alone 43 out of 88 British tanks were destroyed (half by artillery), with only 28 surving tanks limping back, and the rest presumably lost to breakdowns or terrain.

The Somua 35 was as roughly well balanced as the Panzer 38(t), III and IV with somewhat better armour and protection, with a better layout than the very awkward looking Char B1bis, it still had its commander-cum-gunner cooped up in its cramped single turret, with the interior Panzer crew space better laid out.

Yeah, the Pz 35(t) was really important during the first two years of the war as well, although by Barbarossa it was already being superseded by the Pz 38(t), which remained in production until summer 1942 (chassis until the end of the war). The Pz 38(t) was in fact a very good light tank, mechanically reliable, reasonably fast and with a fairly decent armor and gun by 1941 standards. It was clearly better than the T-26 and in practice also better than the BT-7, even though on paper they were a close match.

The B1bis and S35 were designed for somewhat different purpose. The B1bis had heavier armor and a hull mounted low velocity gun for engaging enemy strongpoints and AT guns. Like I wrote earlier, it was basically the first sort of successful implementation of the breakthrough tank. It was equipped with a sophisticated mechanism to aim the horizontally fixed hull mounted gun by turning the whole vehicle, and by all accounts it worked reasonably well, even if it was somewhat expensive and difficult to maintain. The Germans had a healthy respect for the B1bis and often had to resort to Stuka attacks, direct fire artillery and flanking ambush positions with the 37 mm AT guns to stop them. That was of course made possible by the poor coordination between French infantry and tanks.

The S35 was a cavalry tank made for exploitation, basically the French version of the Pz III or the British cruiser tanks. Its greatest shortcoming was the one man turret, which also plagued the B1bis. Unlike the French light tanks for the most part, the S35 and B1bis were provided with radios, but unfortunately the French radios were quite unreliable, which hampered their utilization, and the French infantry often did not have radios at all.

About the German spear formations: more important than the actual formations were the good cooperation between tanks and Stukas and the reliable (for the period) tank radios, as well as cooperation with infantry. The last one was still not fully developed for the invasion of France, but at least the Germans had rudimentary combined arms tactics unlike pretty much everybody else at that point.

[CaptHawkeye]

I think it's also funny that the Russian and Allied armour suffered from a number of the same exact problems during the peroid.

Both the T-34 and Somua had a shitty crew layout and while the T34s turret was slightly better designed, it was still really cramped, the optics for the commander and gunner were poor, and their was no loader. The Tank also lacked an intercom, so comms amongst the crew were not very good. Also i've heard early war Russian AP rounds underperformed. So the T-34s 76mm gun had the in practice performance of a 50-40mm equivalent gun. Not bad for the time, but nothing above and beyond what the Wehrmacht faced in France.

The KV-1 had similar problems to the Matilda II and Char 1B. Of course it's problems were typical of a heavy tank. Poor reliability, too heavy for some bridges and roads, frequent breakdowns, insufficient firepower, etc. In France an encounter with a heavy tank just warranted the nearest group of 88s be rolled up. What was stopping that strategy from being used in Barbarossa?

So like I said, funny how the Germanys *suddenly* found things like this so hard the second time around.

[Big Orange]

It seems that well balanced, less ostentatious (for their time) medium tanks like the Panzer III & IV in the early part of WWII, and the T-34 and M4 Sherman in latter half of the conflict, were more important in winning the battles when used competently enmasse in conjunction with combined arms than the heavier tanks that got great results in isolation and cropped up as the occasional nasty surprise (like the Char B1, KV-1, and Tiger).

Here's a great six part documentary on YouTube about the French, German, and British tanks that were deployed in the Battle of France (TANKS! Fall of France).

[Sea Skimmer]

The KV-1 had similar problems to the Matilda II and Char 1B. Of course it's problems were typical of a heavy tank. Poor reliability, too heavy for some bridges and roads, frequent breakdowns, insufficient firepower, etc. In France an encounter with a heavy tank just warranted the nearest group of 88s be rolled up. What was stopping that strategy from being used in Barbarossa?

Russia is absurdly larger then France and has absurdly fewer roads let alone paved roads across which a towed 88mm flak unit could be moved with any speed. What’s more German troops were so overstretched that defenses simply had no depth at all except for the fortification of the divisional artillery positions. So once a heavy tank broke through the frontline nothing was going to stop it until it ran out of gas, and literally German troops would just have to run away from the things. Shifting other forces to counter attack could take days to arrange due to a lack of lateral communications.

Remember the 88mm in 1941 was not assigned to any regular army division. It was still exclusively a Luftwaffe flak weapon and deployed in independent units. A division was lucky to have one battalion attached, and sitting this battalion forward for anti tank use meant sacrificing its anti aircraft mission. Even then a single battalion only has 16 gun barrels, and if it was a mixed flak battalion which also had 20mm and 37mm guns it only would only have 8-12 88mm barrels. Spread those barrels across a 20km divisional defensive front (The Germans wanted no more then 6-8km divisional fronts but that wasn’t going to happen in Russia) and you don’t have much. Meanwhile on the attack… nearly all those 88mms at the time are towed, and some are horse drawn. Only a few halftrack self propelled 88mm guns existed in 1941 and they totally sucked for anti tank use because of the high profile and lack of protection. Such a large obvious weapon is clumsy to deploy at best. If not for certain Flak 18 design features, mainly that it had depression and a very quick deployment drill, such use would have been largely impossible (clearly anti tank use of the weapon was always intended, course the AP ammo already proved that), and lack of features like this is also why allied anti aircraft guns showed up much more rarely for ground fire despite having similar armor penetration abilities. The Germans also had AP ammo for the 20mm and 37mm flak guns, as both calibers could kill typical 1939 light tanks and some mediums.

In fact the result was precious little coverage by 88mm guns; and actually in both France and Russia it was as or more often that the divisional 105mm and 150mm howitzers which had to be called upon to fight off the heavy tanks. Such artillery weapons could be effective and were more numerous then flak barrels, but using them this way of course meant giving up the indirect role to site the howitzers forward, or else waiting for the normal rearward artillery positions themselves to come under direct tank attack. That in turn means the front line has already collapsed and tanks are swarming forward. Also the lower muzzle velocities of howitzers meant it was harder to hit a tank then with an 88mm gun, all else being equal and ignoring the lack of 360 degree traverse (late war German field howitzers had such traverse, at considerable cost and most such designs like the 128mm howitzer (they also had a dedicated 128mm AT gun people know better) never saw production).

So the solution was more 88mm guns, but simply fielding more towed flak guns doesn’t solve the mobility and tactical siting problems, so the guns had to be self propelled. But even a ‘economical’ self propelled 88mm like the Nashorn still had serious tactical limitations, above all because its light armor left it vulnerable to being knocked out by artillery. Artillery is very underrated (literally the US Army kept doing it into the 1980s when at last they changed the manuals after life fire trials) in its ability to kill stationary armored vehicles with indirect fire. You have to move to escape bombardment. A battle of movement puts high value on a rotating turret, and that’s why the Germans fielded the Tiger/Panther series. Anything less had serious drawbacks… but of course such heavy vehicles also had drawbacks even if they didn't break down so often, and well this all feds into Germany simply fighting a near hopeless war. It means you pick from lists of bad choices.

The Germans also reformulated division TO&Es repeatedly from 1940/41 onward to reduce total manpower while preserving as many heavy weapons as possible, and increasing the number of dedicated anti tank units even at the expense of the field artillery. Lack of field artillery and heavy artillery for counter battery then led German units to just be crushed by walls of Soviet and US shells and get overrun anyway. This lack of manpower also made it harder and harder to attack, since riflemen are key to attacking and they were being pruned away as much as possible. This was bad since German defensive doctrine was heavily based around counter attacks, and on the Russian front you simply could not hold a fixed front line due to lack of manpower to do so.

[Marcus Aurelius]

The Germans also had AP ammo for the 20mm and 37mm flak guns, as both calibers could kill typical 1939 light tanks and some mediums.

The Germans also reformulated division TO&Es repeatedly from 1940/41 onward to reduce total manpower while preserving as many heavy weapons as possible, and increasing the number of dedicated anti tank units even at the expense of the field artillery. Lack of field artillery and heavy artillery for counter battery then led German units to just be crushed by walls of Soviet and US shells and get overrun anyway. This lack of manpower also made it harder and harder to attack, since riflemen are key to attacking and they were being pruned away as much as possible. This was bad since German defensive doctrine was heavily based around counter attacks, and on the Russian front you simply could not hold a fixed front line due to lack of manpower to do so.

It is good to note that the 2 cm KwK 30/38 used in the Pz II was basically the 20 mm AA gun with a somewhat shorter barrel (L/55 instead of L/65). The 37 mm Rheinmetall anti-tank and tank gun was not related to the 37 mm AA gun, however. The latter fired a more powerful and longer cartridge.

The German fetish with tank heavy units was culminated in the independent Panzer-Brigades in 1944, which were brigade size units with no organic artillery or reconnaissance assets. Nevertheless, they worked reasonably well against the Soviets, who had problems with arranging flexible artillery responses themselves. The larger maneuvering space in the Eastern front also allowed the Panzer-Brigades to often surprise Soviet formations with flanking counter-attacks. Needless to say, when deployed to the tighter Western front they did not do nearly as well against the US and other Allied forces which had ample artillery and air support. In this context it is somewhat strange that the US Army did not learn the value of indirect artillery as armor killer, but perhaps lessons are better learned when you are on the receiving end...

[Big Orange]

The 8.8cm Flak 18/36/37/41 and mid to late war heavy tanks that the Germans deployed were ultimately not ideal solutions to winning against the rest of the world, but on a tactical level were still soundly disliked and feared by the enemy, even if the regular Flak 88s must've been relatively slow to set up and more exposed than regular artillery. There was the mobile and somewhat armoured Sd Kfz 8 & 9 half-tracks, but they were originally intended to destroy immobile strong points instead of mobile armour. And then the growing air raids on the Third Reich's industrial areas must've leeched away more and more Flak 88s from the slowly encroaching frontlines...

[Sea Skimmer]

In this context it is somewhat strange that the US Army did not learn the value of indirect artillery as armor killer, but perhaps lessons are better learned when you are on the receiving end...

Wha? The US Army got very good at killing tanks with artillery, to the point that we sent up aerial spotters to use 8in guns, our heaviest field weapon, to pick off specific enemy vehicles deep behind the lines. Many German tanks died this way without ever seeing action; it is of course harder to kill tanks on the attack since they move and start hugging the defenders. Still we used naval gunfire to break up a number of notable axis armored counter attacks on invasions. More then once field guns and howitzers fought with direct fire too; but the failure of the field artillery on the defensive at Kasserine Pass when it was heavily disrupted by Luftwaffe attacks seems to be the only thing most sources record as far as the topic goes.

That’s a problem in general. In the air the fighter and bomber pilots, and on the ground the infantrymen and armor crewmen tend to be the ones who write the most popular books. Many people who experienced the war in different ways just don’t write or don’t get published and we don’t get a balanced perception of the war a lot of the time. A gunner on a 105mm howitzer might have killed hundreds of Nazis personally but because he did it from 11,000 yards away at night while no one saw anything except flashes it isn’t going to make a great story back home. It’s sad that so many veterans are now passing and whose accounts are already lost forever.

[Marcus Aurelius]

The 8.8cm Flak 18/36/37/41 and mid to late war heavy tanks that the Germans deployed were ultimately not ideal solutions to winning against the rest of the world, but on a tactical level were still soundly disliked and feared by the enemy, even if the regular Flak 88s must've been relatively slow to set up and more exposed than regular artillery. There was the mobile and somewhat armoured Sd Kfz 8 & 9 half-tracks, but they were originally intended to destroy immobile strong points instead of mobile armour. And then the growing air raids on the Third Reich's industrial areas must've leeched away more and more Flak 88s from the slowly encroaching frontlines...

Well, the need for the 8.8 cm FlaK became a lot less urgent once the Germans had the 7.5 cm PaK 40 in numbers. Pretty much anything except the IS-2, Churchill VII, Sherman Jumbo and the ISU-122/152 could be killed with the 75 mm AT gun fairly easily. Well, the SU-100 and the M26 were resistant as well, but those arrived late and in small enough numbers initially that it hardly mattered.

[Mr Bean]

Well, the need for the 8.8 cm FlaK became a lot less urgent once the Germans had the 7.5 cm PaK 40 in numbers. Pretty much anything except the IS-2, Churchill VII, Sherman Jumbo and the ISU-122/152 could be killed with the 75 mm AT gun fairly easily. Well, the SU-100 and the M26 were resistant as well, but those arrived late and in small enough numbers initially that it hardly mattered.

Pzg40 for the Pak 40 always in rare supply could deal with all of those tanks sans the IS2 and Churchill VII from the front. As for the Su-100 I've never read any accounts of 1000 meter engagements the Pak having issues. Maybe at 2000 which could happen but the Su-100 which was itself just a remake of the Su-85 was just at it's core a T-34 with better frontal armor. But not KV or IS level.