Pz.Kpfw. I

The Pz. I Ausf. A was the first mass-produced German tank. In 1935, the design was upgraded with an elongated hull and a more powerful engine. Mass production of this version, the Pz. I Ausf. B, eventually totaled 675 tanks. The standard armament was weak, but some tanks were upgraded on the Spanish Civil War battlefields to accommodate 20-mm guns.