The Sd.Kfz. 251 (Sonderkraftfahrzeug 251) half-track was a World War II German armored personnel carrier designed by the Hanomag company, based on its earlier, unarmored Sd.Kfz. 11 vehicle. The Sd.Kfz. 251 was designed to transport the Panzergrenadier (German mechanized infantry) into battle. Sd.Kfz. 251s were the most widely produced German half-tracks of the war, with at least 15,252 vehicles and variants produced by seven manufacturers. Some sources state that the Sd.Kfz. 251 was commonly referred to simply as "Hanomags" by both German and Allied soldiers after the manufacturer of the vehicle; this has been questioned, and may have been only a postwar label. German officers referred to them as SPW (Schützenpanzerwagen, or armored infantry vehicle) in their daily orders and memoirs. Design There were four main model modifications (Ausführung A through D), which formed the basis for at least 22 variants. The initial idea was for a vehicle that could be used to transport a single squad of 10 panzergrenadiers to the battlefield protected from enemy small arms fire, and with some protection from artillery fire. In addition, the standard mounting of at least one MG 34 or MG 42 machine gun allowed the vehicle to provide suppressive fire for the rifle squad both while they dismounted and in combat. The armour plates were designed to provide protection against standard rifle/ machine gun bullets (like the 7.92×57mm Mauser bullet). The front-facing plates were 14.5mm thick; the sides were steeply angled, V-shape 8mm thick plates. This level of armour provided protection against normal (non-tungsten) rifle AP round, which could pierce about 8mm of vertical armour. Positive aspects of the open top included greater situational awareness and faster egress by the infantry, as well as the ability to throw grenades and fire over the top of the fighting compartment as necessary while remaining under good horizontal cover. The downside, as with all armored personnel carriers of the era, was a major vulnerability to all types of plunging fire; this included indirect fire from mortars and field artillery, as well as small arms fire from higher elevated positions, lobbed hand grenades, Molotov cocktails, and strafing by enemy aircraft. The first two models (Ausf. A and B) were produced in small numbers from 1939. Ausf. A and B models can be identified by the structure of the nose armor, which comprised two trapezoidal armor panels - the lower of which had an engine cooling