With a mummy shape and Thermolite® Pro fabric, the Reactor Liner uses new infrared technology paired with comfortable stretch fabric to offer extra warmth, versatility, and increased insulation.The drawcord allows you to open or close the footbox allowing you more control of temperature and your comfort. Best suited to cold conditions.FeaturesThermolite Pro has engineered hollow fibres like standard Thermolite, but with the addition of permanent ceramic pigments that absorb the body's infrared rays and reflect them back to the wearer.The recycled Thermolite EcoMade fibres are made from 100% textile waste, are GRS-certified, and offer the same quality and durable lightweight warmth as their polymer virgin counterparts but with a lower carbon footprint.Sea to Summit Liners are treated with HeiQ Fresh FFL, a biocide-free, highly effective odour control technology that uses a bio-based Amino Sugar Polymer to neutralise body odour.Mummy shapeThermal Boost - Tested in accordance with ASTM D1518-20143-Season Sleeping Bag: +6%1-Season Sleeping Bag: +12% Sea To Summit Reactor Sleeping Bag Liner - Mummy with Drawcord - Compact