They mounted either the modified ex-Soviet 76.2 mm F-22 Model 1936 divisional field gun, or the German 7.5 cm PaK 40, in an open-topped fighting compartment on top of the chassis of the Panzer 38(t). They offered little protection to the crew, but added significant firepower compared to contemporary German tanks. They were in production from 1942 to 1944 and served on all fronts until the end of the war, along with the similar Marder II.