Military Outdoor Clothing Previously Issued U.S. G.I. Modular Sleeping Bag System (4-Piece) US GI 4-piece modular sleep system; used military surplus Includes OD patrol sleeping bags black intermediate sleeping bag, woodland Gore-Tex bivy cover, and black compression stuff sack Can be used in conjunction with each other or separately Provides comfort from 50 degrees F to -30 degrees F Snaps to the Bivy for use in slightly colder-wet zones. Insert the Intermediate Bag inside for colder extremes