The
sIG 33 gun was used as direct-fire artillery in support of assaulting infantry. To improve its mobility 38 guns were mounted on a
Panzerkampfwagen I chassis in February 1940. The
15 cm sIG 33 (Sf) auf Panzerkampfwagen I Ausf B that had participated in the
Invasion of France in 1940 had proven to be too heavy for its
chassis as well as being enormously tall. The same gun was mated to the
Panzerkampfwagen II chassis in an attempt to drastically lower its height while using a stronger chassis. The prototype used a standard
Panzer II Ausf. B chassis when it was built in February 1941, but this was too cramped for use. The chassis was lengthened by , which required adding a sixth roadwheel, and widened by to better accommodate the gun while preserving its low silhouette. plates formed the front and sides of the open-topped fighting compartment, which was also open at the rear. Its sides were notably lower than the front, which made the crew vulnerable to small arms fire and shell fragments. Large hatches were added to the rear deck to better cool the engine. The vehicle carried 30 rounds for the gun which could
traverse a total of 5° left and right and used a Rblf36 sight. == Combat use ==