Ordnance provision system. [Ordnance catalog (ordnance provision system): Group G, Half-track vehicles, car, half-track, M2. carrier, personnel, half-track, M3, carrier, 81-mm mortar, half-track, M4, carriage, motor, 75-mm gun. M3, sec. 4, Rear axle (jackshaft) group; Feb. 16, 1942.