The Reactor Fleece Liner is made from Thermolite® Pro hollow fibers used in a mesh pattern to provide the warmest inner sleeping bag. You can adjust the temperature with the zippers on the shoulders and the drawstring at the bottom of the legs , which also perfectly matches the Free Flow-Zip system of the Sea to Summit sleeping bags.

The versatile Reactor Fleece Liner provides multi-season comfort or can even be used as a standalone sleeping bag in warm weather. Additionally, the drawstring at the bottom of the legs allows for plenty of ventilation and the ability to walk around camp without having to remove the liner.

The inner sleeping bag has HeiQ Fresh odor control technology to help keep the pad fresh even after prolonged use.

The mummy shape is designed for maximum thermal efficiency and includes zips on the shoulders and a drawstring at the bottom of the legs for additional temperature regulation.