Items included with this listing. Green Patrol Sleeping Bag. Intermediate Cold Weather Black Core Bag. Woodland Camouflage Goretex BIVY Cover. Black Compression Stuff Sack. The Modular Sleep System (MSS) is a bag-within-a-bag style sleeping bag system, developed in 1997 for the United States Army. The MSS consists of a camouflaged, waterproof, breathable Bivy Cover. A lightweight Patrol Sleeping Bag. And an Intermediate Cold Weather Sleeping Bag. A Compression Stuff Sack. Is included to store and carry the system. The patrol bag provides cold weather protection from 35 to 50 degrees Fahrenheit. The intermediate bag provides cold weather protection from minus 5 to 35 degrees Fahrenheit. Together, the patrol bag and intermediate bags provide extreme cold weather protection in temperatures as low as minus 30 degrees Fahrenheit. The bivy cover provides environmental protection from wind and water. Sleeping bags are made of ripstop nylon fabrics and continuous filament polyester insulation; camouflage bivy cover is made with waterproof, breathable, coated or laminated nylon fabric; the compression sacks are made with water-resistant, durable nylon fabric. The MSS components can be combined in different configurations to match the environment and temperature needed. Each component has double sided snaps down both sides of the zipper that securely attach each component to the other. These snaps essentially allow two or three components attached together to function as a single sleeping bag.