The Sea to Summit Reactor Thermolite Liner adds up to 15 degrees of warmth to a sleeping bag or, use alone as a warm weather bag.

The Reactor Liner is made from the lightest weight DuPont Thermolite®. Thermolite is a hollow core fiber that provides extraordinary warmth for its weight and remains extremely breathable. Thermolite has hollow-core fibers that trap insulating air.

Its mummy shape with box foot is thermally efficient. Draw cord hood with mini cord lock allows you to adjust for optimal comfort. Packs into its own 3” x 5” sil-nylon stuff sack.