JACKET-WINTER,FLYING SUIT or J-WFS was formally manufactured as a Navy flight suit between 1954 and 1975. Because the official name is confusing, it is generally referred to as WEP (Wep), which is an abbreviation of Burea of Naval Wepons (BuWEPS) on the label, and not the official name. This jacket features a 66 nylon outer shell with a thin cotton lining. The cotton used for the lining is distictive and is sometimes mistake for synthetic fibre due to the texture of the hard twist thread used to weave the fabric.