The B3 jacket was brought into service around 1934 and was especially designed to provide those men who were working and living 30,000 feet up in the sky in the B-17s with ultimate protection and warm. Most B3s were made of half-inch pile, constructed of shearling pelts with fur inside and the leather out. The first jackets were matte finished and only by the late 1930s did they start to be dyed in seal brown. Laquer was used to coat the jacket, but tended to crack with use.
The B3 jacket came in many shapes and sizes: some had one collar closure strap, others had two. They might have one or two patch pockets and some had leather reinforcing patches from the shoulder to the wrist.The wool pile was visible at the cuffs and at the waist.