Reproduction of the legendary D-1 Lightweight sheepskin jacket with two zip pockets. Originally the D-1 Jacket was used by USAAF ground crew personnel, often working in bad weather conditions. Considering that the D1 was designed to be a ground crew jacket, a surprising number of them found their way into the air. Because of its simple design, choice of medium weight sheepskin, and lack of bulk compared to the B3, many pilots traded in their B3s for the D1. This was a good deal for both the mechanic, who had a warmer jacket for working outdoors in severe weather, and the pilot, who could now wear a D1 over an A2, giving him an extra layer of protection at high altitudes, in addition to better comfort.