The THERMOLITE®Pro Reactor Extreme liner is Sea to Summit’s warmest knitted sleeping bag liner. If your adventures take you to colder climates, the Reactor Extreme will add plenty of warmth to a sleeping bag. Plus, in warmer weather, it can be used as a ‘stand alone’ sleeping bag. With a mummy shape and Thermolite® Pro fabric, the Reactor Extreme Liner featuring a drawcord uses new infrared technology, which reflects the body's infrared heat back to you, paired with comfortable stretch fabric to add warmth, versatility, and increased insulation. The Reactor Extreme feature offers additional heat retention best suited to cold conditions. Features Traps insulating air to increase warmth of a 1 season sleeping by up to 15% and 7% for a 3 season bag Sustainable construction- 50% Thermolite®EcoMade All-Season fabric, which is made with 100% textile waste and GRS Certified, and 50% Thermolite Pro with infrared technology Treated with Heiq Fresh FFL biocide-free effective odour control Technical mummy-shape with drawstring hood. Easy care – machine wash with no special soap needed. Avoid fabric softeners and dryer sheets. Packs into its own Ultra-Sil stuff sack Max User Height 198 cm Weight 364 g Packed Size 12 × 15 cm The reactor extreme is perfect for… Backpackers whose sleep system will be used in colder climates Campers whose sleeping bags don't keep them warm at the advertised temperature Very warm-weather campers who don't need a full sleeping bag Campers or backpackers looking to extend the performance of a (perhaps older) sleeping bag into shoulder seasons For maximum Thermal Boost choose the Reactor Fleece Liner Reactor Extreme Sleeping Bag Liner - Mummy with Drawcord - Regular