The Type L-2B was a definitive edition to the light-zone category. It was standard USAF issue until replaced by the CWU 36/P jacket in the late 1970's. The essential differences between the L-2A and L-2B are colour and the way the size is format is indicated on the label: L-2Bâ€™s were changed to Sage Green from USAF BLUE, and the sizing format changed to S, M, L & XL.Size specs. were also changed to create a roomier fit, and the composition of the nylon outer fabric was changed to 2/2 heavy nylon twill from 1/3 twill. Additionally the lining material was changed to wool-and-rayon from a wool-and-nylon blend.MATERIAL : Mil spec. 2/2 Heavy Nylon TwillCOLOUR : Sage GreenLINING : Wool 35% Rayon 65% Double Face BrushedKNIT PARTS : Mil spec. 100% WoolZIP : Crown Aluminium Auto LockSNAP : Mil spec. Brass Black OxidizedLABEL : Tops Apparel Mfg. Co., Inc.