Make your sleeping bag extra warm and toasty on cold nights at the campground. The Sea to Summit Thermolite Reactor Extreme increases sleeping bag performance by up to 25 F (14 C) with super-insulating 110g/m Thermolite fabric. Thermolite is a hollow core fiber that provides extraordinary warmth for its weight and remains extremely breathable. Spacious design allows for a comfortable night's sleep, even when the mercury plummets. Perfect for extending the season of your sleeping bag.Features: 110g/m2 Thermolite construction throughout Adds up 25° F to warmth to a sleeping bag Mummy shape with a box foot Draw cord hood with mini cord lock Packs into its own Ultra-Sil stuff sack Specs: Length: 84" Width: 36" Weight: 14 oz Temp Rating: Up to 25 F