The 3.7 cm KwK 36 L/45 (3.7 cm Kampfwagenkanone 36 L/45) was a German 3.7 cm cannon used primarily as the main armament of earlier variants of the German Sd.Kfz.

141 Panzerkampfwagen III medium tank.

It was essentially the 3.7 cm Pak 36 modified for use in a rotating enclosed turret.

Average penetration performance established against rolled homogeneous steel armor plate laid back at 30° from the vertical.

2. http://www.wehrmacht-history.com/heer/panzer-armaments/3.7-cm-kwk-36.htm Archived 25 February 2014 at the Wayback Machine