Sea to Summit is a small, privately owned global company which develops and manufactures outdoor, travel and water sport products. They provide solutions for outdoor enthusiasts looking for innovative, durable, lightweight and compact gear. Sea to Summit continues to research the best materials, production methods and ideas for new products keeping us at the forefront of bringing lighter, better made, better performing gear to enthusiasts around the world. The Thermolite Reactor Extreme increases sleeping bag performance by up to 15C with its super insulating 110g/m Thermolite fabric. Spacious design allows for a comfortable nights sleep, even when the mercury plummets. Thermolite is a fibre with a hollow core that provides extraordinary warmth for its weight while remaining extremely breathable. The Thermolite Reactor Extreme adds warmth to a sleeping bag or, used alone, is ideal as a warm weather bag. With the stretchy knit fabric that moves with you and a draw cord hood, this liner is perfect for wrigglers and rollers or anyone who needs some extra warmth. The Sea To Summit Thermolite Reactor Extreme sleeping bag liner adds up to 15C warmth to your sleeping bag. It is also machine washable to help you keep your sleeping bag clean and fresh. In warm climates it can be used as a stand alone super compact sleeping bag.