The 3.7 cm Panzerabwehrkanone 36 was often abbreviated as PAK 36. These guns were first developed in 1933 by the firm of Rheinmetall. They remained in production until 1942. These guns were designed to be an antitank gun but the 37mm round proved too weak to punch through allied armor.  These were replaced after 1941 by the much more powerful 75mm PAK 40. In 1943 these guns regained some usefulness with the introduction of the Stielgranate 41 shaped charge. This rocket type round gave it the ability to penetrate allied tanks but it have a very limited range. ​
These photographs were taken from a number of online sources and auction sites.  They are presented here for educational purposes.