The THERMOLITE® Reactor liner is our best-selling and lightest thermal sleeping bag liner. Featuring a mummy shape and Thermolite® Pro fabric, this liner incorporates new infrared technology and stretch fabric to provide additional warmth, versatility, and enhanced insulation. The drawcord allows for added adjustability, ensuring maximum comfort. It's ideal for use in cold conditions. Features Thermal Boost of 12% when used in a 1 season sleeping and 6% in a 3 season bag Stretchy, Thermolite® Pro fabric is incredibly comfortable and utilises Infrared Technology to increase warmth without adding weight. Lighter weight and more packable than fleece. Technical mummy-shape and available with or without a drawstring in the hood hood Easy care – machine wash with no special soap is needed. Avoid fabric softeners and dryer sheets. HEIQ Fresh bio based treatment for added odour control Keeps sleeping bag clean. Packs into its own Ultra-Sil stuff sack. ADDED WARMTH: Up to 6% in a 3 season bag and +12 in a 1 season BEST USE: Backpacking, Camping COMES WITH: Ultra-Sil stuff sack MATERIAL(S): 50% Thermolite Pro & 50% Thermolite EcoMade SHAPE: Mummy The Sea to Summit Reactor Sleeping Bag Liner is a lightweight, top-selling thermal sleeping bag liner, designed for cold conditions. Its mummy shape and Thermolite Pro fabric utilise advanced infrared technology to reflect body heat and provide exceptional warmth. The comfortable stretch fabric enhances insulation, while the drawcord adds flexibility for a snug fit. Ideal for adding warmth and versatility to your sleeping bag, it ensures premium comfort in chilly environments.Smart design: The technical mummy shape with a drawstring hood ensures a snug fit and enhanced warmth.Low Maintenance: Easy care design allows for hassle-free maintenance and long-lasting use.Compact Storage: It conveniently packs into its own Ultra-Sil stuff sack for compact storage.Odour Control: The FFL biocide-free treatment provides effective odour control without harmful chemicals. The Reactor Liner - Standard is Sea to Summt's top selling and lightest thermal sleeping bag liner. With a mummy shape and Thermolite Pro fabric, the Reactor Liner uses infrared technology paired with comfortable stretch fabric to offer extra warmth, versatility and increased insulation which delivers a substantial thermal boost for enhanced comfort during outdoor adventures.