This is a reproduction Navy SEAL "Float Coat" this was the improved version of the earlier "Snap Vest", the main changes were built in sleeves, smaller pouches on the sleeves for first aid dressings/compass and the production of the coat in 3 versions; Rifleman, Radioman and Grenadier (the latter two shown below).
The jacket has a genuine Floatation Bladder inside and the top up valve and quick-inflate device can be seen on the shots of the inside. There were 1,200 jackets produced with 1/2 of these being Riflemans Jackets and the remainder being split between the Grenadier and Radionman versions. 500 were sent to Seal Teams 1 & 2 and then 100 jackets each to the UDT teams 21 & 22.
In use many jackets were modified by turning them into vests by romoving teh lower pockets and sleeves to make them easier to jetison in an emergency. The Radiomans version was very unpopular as you had to remove the radio to remove the jackets, the floatation bladder was also cut-down on this version and didn't support the extra weight of the radio.
Shot of the reverse of the jacket showing the four shoulder magazine pockets
Detail of the top up air valve
Detail of the self inflation device, the gas bulb itself is missing
The chest magazine pouches each hold two 20 round M16 magazines