The Snugpak Special Forces Complete System -4 Degree Mummy Sleeping Bag is a center zip modular system comprising of the Special Forces 1 Bag for use above freezing temperatures and the Special Forces 2 Bag. Both bags come with their own stuff sack, reinforced foot and quick release center zip, for when you need to get out of your sleeping bag in a hurry. Supplied with an extra zip baffle to allow both bags to be used together and retain the convenience of closing and opening with one quick release zip. These sleeping systems are designed to be layered together to cover all different types of weather conditions.FeaturesUse together in extreme conditions or separatelyZips together easilyBoth components come with their own compression stuff sackSupplied with a zip baffleComfort level of 5 degree F