This APC was based on the AS 37 truck, which in turn derived from the TL 37 AS, the desertized version of the TL 37 artillery tractor. The S37 was not intended as a carrier for armored infantry, but rather as a battlefield command/supply vehicle. The overall design was simple because the vehicle on which it was based on required very little modification. The engine was at the front, allowing for a large boxy armored superstructure over the back with an open-top to provide protection for troops being carried. A very unusual split two-piece rear door provided access with the top half overlapping the lip of the bottom half of the door. Armor consisted of armored steel plates, flat and cut to size, bolted to a steel frame. Plate thickness ranged from 6 mm to 8.5 mm thick providing protection from small arms fire and shell splinters, although the lack of a roof left the soldiers vulnerable to shrapnel or fire from above. On the other hand, the lack of a roof provided a significant amount of cooling for the cabin, which otherwise, under desert conditions, would have become unbearable. About 200 were built.
A few were sent to North Africa. Despite being equipped and designed for use in hot desert conditions to support the war in North Africa, the A.S.37 found use in Yugoslavia, fighting partisans and for convoy escort duties. Vehicles were issued to the 31st Regiment (Siena), the 955th Sezione Autoprotetti with the 1118th Autosezione of the Macaerta Division, the 259th Autoreparto Autoprotetti of the 5th Autogrippo (Trento), the 1034th Sezione Autoprotetti of the 71st (LXXI) Battalion Motociclisti (6th Regiment Bersaglieri) and the 1034th Sezione Autoprotetti of the 11th Autoreparto Pesante (Albania). By the end of April 1943, there were still 102 vehicles operational there with Italian forces. The AS37 in German service was renamed Gepanzerte Manntransportwagen S.37 250(i) (gp.M.Trsp.Wg.S.37 250(i)) and saw service, not just against partisan forces, but also against the Soviets and Bulgarians at the end of the war. The A.S.37 was operated by the 7th SS-Freiwilligen-Gebirgs Division "Prinz-Eugen" and also some Wehrmacht units.











