The Canadian Army sleeping bag system, also known as the Sleeping System Outfit, Extreme Cold Weather or the SSOECW, typically consists of three main insulation/barrier layers that form a modular system. The system is designed to be used in various combinations, with all components used together for extreme Arctic conditions down to -50°C. 
 
They are a tried and true piece of Canadian kit that has been used by the Canadian forces since the 1960s.
 
They Contain:
 
Inner Bag: A down-filled mummy-style bag.
Outer Bag: A slightly wider down-filled mummy bag, allowing the inner bag to be nested inside.
Liner: A cotton or flannel liner that serves to keep the bags clean and provide additional comfort/warmth.
Bivy Bag (Gore-Tex): A waterproof and breathable outer shell that acts as the final barrier against snow, wind, and rain.
Detachable Hood: A synthetic-insulated hood to seal the system around the head
Compression Storage Bag 
 
While we generally sell them as a 6-piece system, we do offer the option to buy each piece separately in order to customize pre-existing sleep systems, or to accommodate your seasonal needs!