Made of 5.5 oz (9.1 oz/ly, 186 g) 50/50 cotton/polyester, the t-shirt has a set-in rib collar with shoulder-to-shoulder taping. Double-needle sleeve and bottom hems. Preshrunk to minimize shrinkage.
The Mk V was designed as an interceptor to counter high-altitude reconnaissance Ju-86. It was equipped with a 1440 hp Merlin 45 engine and compressors. The first one flew in June 1941.