The Sea to Summit Reactor Extreme Sleeping Bag Liner is designed for cold climates, utilizing Thermolite® Pro fabric and infrared technology to reflect your body's heat and enhance warmth. Its mummy shape with a drawstring hood ensures a snug fit. The liner is easy to care for with biocide-free odor control and conveniently packs into its own Ultra-Sil stuff sack for compact storage. It can add significant warmth to your sleeping bag, increasing it by up to 15% for a 1-season bag and 7% for a 3-season bag. Made with sustainable materials including 50% Thermolite® EcoMade fabric, it offers breathability, moisture-wicking properties, and flexibility. The HeiQ Fresh odor control technology keeps the liner fresh for extended use, making it ideal for multi-day treks and winter camping. It can also be used as a standalone sleeping bag in warmer weather.