The M1 Flyers Vest was a flak jacket used by American bomber crews during World War II.
The vest was made up of three pieces, each with small, two-inch strips of Manganese steel plating embedded under the nylon. Said pieces were 1 mm thick. Its purpose was to protect bomber crew members against the low velocity shrapnel that would often puncture the sides of aircraft flying through Axis air defense. After analysis, it was found that 36% of crewmen that did not wear the vest were killed, with a further 69% wounded.  With the vest however, casualty rates dropped to 18% killed and 13% wounded. Through personal experience and the experiences told by fellow crewmen, most American bomber crew eventually opted to adopt the vest, despite its 7 kilogram weight, 11 kilograms when combined with the M3 Flyers Apron.
The backing of the vest was initially intended to be made of linen, though this proved unavailable and cotton was used until its later replacement by nylon. One of the most important features of the vest was its red quick-release tab placed on the front of the vest. Pulling it would release the vest entirely, allowing personnel to quickly discard their heavy vest and bail out of the aircraft. To avoid exhaustion however, it was common to only put on the vest when the aircraft came under fire.
- M2 Flyers Vest: Slightly different version of the M1, designed for pilots and other personnel who remained in a seat with an existing armored backing, and thus had an unarmored back piece. Was standardized at the same time as the M1.
The M1 Flyers vest began its history in 1942 following the issuing of a similar design for RAF bomber crewmen flying missions over German territory. These examples were too heavy and too immobile, however, for the particularly cramped RAF aircraft and were accordingly dropped from service. Inspired, Colonel Malcolm C. Grow, Chief Surgeon of the Eighth Air Force, noticed that many of the wounds he was treating could easily have been prevented, leading him to creare the M1 design. He was awarded the Legion of Merit for his work a short while later. The M1 Flyers Vest was officially adopted by the US Army Air Forces as standard equipment on October 5, 1943. From then on, some 338,780 M1 vests were produced until July 1945 along with an additional 95,919 M2 vests.
- ↑ http://www.iwm.org.uk/collections/item/object/30106963
- ↑ http://history.amedd.army.mil/booksdocs/wwii/woundblstcs/chapter11.htm
- ↑ Bowman, Martin. Eager Eagles: The U.S. Eighth Air Force in Europe, 1941-43. Stackpole Books (2013), Page 104
- ↑ http://www.flightgear.ch/USA_Heavy_Bomber_Crew_2/usa_heavy_bomber_crew2.htm