There were two main types of self-propelled guns in the German Army during WW2. One was fitted with an anti-tank gun and the other with an artillery howitzer, like the 10.5cm leFH 18 (Sf.) auf Geschutzwagen 39H(f) self-propelled gun. The vehicle fitted with the artillery howitzer was called a ‘Geschuetzwagen’, which is literally translated as a ‘gun vehicle’. The letters ‘SF’ stand for ‘Something I'm not typing’ – self-propelled carriage. The letter (f) indicates that the chassis was of French origin. Improvised self-propelled artillery guns were developed to enable fast moving attacks to have artillery support that could keep up with the speed of advancing Panzer Divisions. They could use direct fire mode at targets they could see or, more commonly, use indirect fire at targets plotted on a map. They were not designed to be in the front line or engage in combat with tanks. They were motorized artillery guns that could fire high explosive HE shells over the heads of friendly troops. Most targets would have been given to the crew as map grid references by forward observation officers or infantry units under attack.
They were cheaper and faster to build than a new vehicle. They used the chassis of an obsolete captured French tank and an existing artillery howitzer. Putting the 10.5cm leFH 18 howitzer on top of the Hotchkiss tank chassis was a more efficient use of manpower from the traditional form of German artillery battery transportation. Even in WW2, horse power was still widely used although tracked vehicles were also used when available. Each field gun would require a six-horse team to pull the gun and limber. The ammunition, supplies and kit would be kept in the limber, which was a very large box on a pair of wheels with seats on the top. Three men would ride on the left hand horse of each pair to control them. The remaining six men of the gun crew would ride on top of the limber. Only a relative few were towed by the 3 ton halftracks. At least twenty four 10,5 cm LeFH 16 and 10,5 cm leFH 18 (Sf.) auf Geschutzwagen 39H(f) self-propelled guns went into action in Normandy in June 1944.