The SdKfz 251 halftrack was a highly successful design with a bewildering array of variants produced during World War II. The 251/10, for example, was a halftrack equipped with a 3.7cm PaK 36 anti-tank gun. This small-caliber weapon designed by Rheinmetall first appeared in 1936, but by the time World War II broke out it was outdated and ineffective against more heavily armored enemy tanks. Thus, a number of these �door knockers" (as the gun was sometimes nicknamed by German troops) were mounted on the hull superstructure of some German halftracks to provide light and mobile anti-armor support.Main features include new one-piece 3.7cm PaK with hollow muzzle made by slide mold, new roof plate for mounting AT gun, armored shield with bolt detail, gun cradle with accurate detail, accurate gun shield stays and hand wheels, road wheels injected as a unit - convenient to assemble and saves time, photo-etched parts for upgrading detail, DS tracks, and Cartograf decal offering accurate markings.