The Pak 35/36 was introduced in 1928 and was developed by Rheinmetall. It was first used in 1936 during the Spanish Civil War. The KwK 36 L45 was the same gun as appeared on early versions of the Panzer III. The Pak 41 was a light anti tank gun issued to German airborne units. The Pak 41 was based on a modified Pak35/36 carriage but used squeeze bore principles to boost it's velocity giving it better armour piercing abilities.