The M1 helmet is a combat helmet that was used by the United States military from World War II until 1985, when it was succeeded by the PASGT helmet. For over forty years, the M1 was standard issue for the U.S. military. The M1 helmet has become an icon of the American military, with its design inspiring other militaries around the world.
The M1 helmet is extremely popular with militaria collectors, and helmets from the World War II period are generally more valuable than later models. Both World War II and Vietnam era helmets are becoming harder to find. Those with (original) rare or unusual markings or some kind of documented history tend to be more expensive. This is particularly true of paratroopers' helmets, which are variants known as the M1C Helmet and M2 Helmet.
The M1 helmet was adopted in 1941 to replace the outdated M1917 A1 "Kelly" helmet Over 22 million U.S. M-1 steel helmets were manufactured by September 1945 at the end of World War II. A second US production run of approximately one million helmets was made in 1966–1967. These Vietnam War–era helmets were different from the World War II/Korean War version by having an improved chinstrap, and were painted a light olive green. The M1 was phased out during the 1980s in favor of the PASGT helmet, which offered increased ergonomics and ballistic protection. It should be noted that no distinction in nomenclature existed between wartime front seams and post war shells in the United States Army supply system, hence World War II shells remained in use until the M1 was retired from service.
While obsolete in the United States, the M1 Helmet and international variants are still in use by other nations around the world. The M1 helmet liner still occupies a symbolic niche in the United States military. For example, liners are currently worn in training by United States Navy SEALs BUD/S candidates, where in it is painted with the trainees' class number, name, and rank insignia, and painted and chrome-plated versions models are still used in ceremonial units. In Israeli service, reserve soldiers have used the M1 helmet in combat as late as 2006.