The one piece coverall was part of the Army clothing inventory throughout the war. Originally issued only to mechanics and armor crews (such as the tank crew in the photo), the comfortable and inexpensive garment was later used by truck drivers, signal corps linemen, and also for general infantry use, especially the jungle version for troops in the Paci c. There were two main types issued to the Army before and during World War II.
The one-piece herringbone-twill work suit was initially only issued to mechanics and to personnel of the Armored Forces. It was designed with a bi-swing back, a belt, two breast pockets, two patch hip pockets, a watch pocket and one leg pocket. Other than the mechanics and armored personnel, all other enlisted men received a two piece work suit (fatigues), also of herringbone-twill.
The right-hand breast pocket has a buttonless ap, a distinguishing feature of the 1938 Model I pattern. The suit is opened and closed by one zipper. The two back hip pockets are patch style, open without a ap cover. There is a buttoned passthrough on one hip pocket.