View of workers assembling wooden crates on the packing line at Plant 4, Service Dept., Bldg. 20, Operations Civilian and Military, GMC Truck & Coach plant. Materials are stored on shelves in background. Printed on front: "GMC Truck & Coach Division." Handwritten on back: "Plant 4, Service Dept., Bldg. 20, Operations Civilian and Military. Packing line, first floor. Factories--GMC, ca. 1943."