Supplied by the U.S. Navy, the M1926 life belt was issued to soldiers participating in Operation Overlord. The belt could be inflated using two CO2 cartridges, or manually via two valves (the belt had two internal inflatable tubes).
Worn properly the life belt was to be positioned as high as possible below the armpits so as to keep a soldier's head above water. Despite its name, the life belt was not meant to be worn around the waist, where it could flip a soldier upside down and drown him.
Although designed for personal use, the life belts were also used to float equipment and supplies in case a landing craft was to capsize or sink. Manufacturers of the life belt included the Firestone Tire and Rubber Co. and the U.S. Rubber Co.
The M1926 life belt can be seen many times during the opening fight for Omaha Beach, including its use as a makeshift flotation system for equipment. During the triage scene on Omaha Beach, a low-quality lifebelt prop can be seen (see screenshot 6)
Paratroopers would have worn USAAF-issued B4 ("Mae West") life preservers during their combat jumps into Normandy, but none of these are actually seen in the film. Small numbers of paratroopers were issued the M1926 life belt instead of the B4, probably due to equipment shortages.