The THERMOLITEA(R) Reactor(TM) Compact sleeping bag liner is the ideal choice for gram counters under 6 feet who want to add warmth to their sleep system. The world&&';;s first 'hybrid&&';; sleeping bag liner uses a combination of two weights of THERMOLITEA(R) fabric, with the warmer fabric strategically positioned across the torso and in the footbox. The hollow core THERMOLITEA(R) fibers work like the hollow fur of a polar bear to trap extra insulating air. The Reactor Compact Plus keeps your sleeping bag clean and is super easy to wash. It will bump up the warmth of your sleeping bag considerably, depending on your metabolism, your sleeping bag and sleeping pad, and the environment. Learn more about which liner is right for you HERE Highlights Best Use Backpacking, Bike Touring, Travel, Camping Warmth Adds up to 20AdegF to the temperature range of your sleeping bag Bonus Easy to wash and dry. Helps to keep your down or synthetic-insulated sleeping bag cleaner for longer Features Adds up to 20AdegF /11AdegC of warmth to a sleeping bag Lighter weight, more packable than fleece Mummy shape with a box foot Drawcord hood with mini cord lock Packs into its own Ultra-Sil(TM) stuff sack FAQ&';s Is this thermal sleeping bag liner...? Suitable for use with a rectangular / wide sleeping bag? The knitted fabric of the Reactor is so stretchy that you won&&';;t feel the shape of the liner at all. Useable as a stand-alone sleeping bag in warm weather? Check our blog to learn about conditions where this would work. Equipped with a zipper? The beauty of our sleeping bag liners is their minimal weight and packed size, and a zipper would significantly increase both. Please note: The packaging of this liner includes the size description 'Short&&';;. This refers to the 6-foot / 183cm overall length; there is no 'Regular&&';; or 'Long&&';; Reactor Compact Plus available in North America.