View of workers operating machinery at Plant 1, GMC Truck & Coach plant. Printed on front: "GMC Truck & Coach Division." Handwritten on back: "Plant 1. Machine shop & Heat Treat Dept. Dept. 4, machining operations on tire inflation. DUKW parts and 7-70 parts, machine shop, Bldg. 12. Factories--GMC, ca. 1943."