REAL McCOY's TYPE A-3 Mechanic Cap Size: 7 1/4 Head circumference is about 57cm. A mechanic cap issued to Army aviation maintenance personnel. During World War II, it was confirmed that it was worn by pilots as well as ground crew. The style of wearing it with the brim up seems to have been popular at the time, and it is recorded in many photos from that era. This product is a used item. If you are looking for perfection or are nervous, please consider carefully and only purchase after you are satisfied with your questions and have resolved any doubts.