Sonderkraftfahrzeug (abbreviated Sd.Kfz.,[1] German for "special purpose vehicle") was the ordnance inventory designation used by Nazi Germany during World War II for military vehicles; for example Sd.Kfz. 101 for the Panzer I.
Sd.Kfz. numbers were assigned to armored, tracked, and half-tracked vehicles in military service with Nazi Germany before and during World War II.