An essential component in your sleep system, the Reactor Extreme liner with Thermolite® Pro fabric utilizes innovative infra red-absorbing ceramic pigments to give your system the thermal boost needed in colder-weather adventures. The soft, wicking stretch-knit fabric provides unmatched comfort and freedom of movement while still allowing the Reactor Extreme liner to fit any sleeping bag. Additionally, the drawcord footbox offers plenty of ventilation and the versatility of walking around camp while still wearing your liner if needed. Features Thermal boost to retain heat and warmth. As the core of your sleep system the Reactor liner extends the performance of your sleeping bag and sleeping mat in the coldest of conditions Thermolite® Pro technology using knitted, hollow-core fibers and infrared-absorbing ceramic pigments to reflect your body's heat back for enhanced warmth and comfort Drawcord footbox and shoulder openings can be opened or closed for optimal comfort and integrates perfectly with the footbox of our Free-Flow Zip system in select Sea to Summit sleeping bags HeiQ Fresh odor control technology helps keep the liner fresh even after extended use Knitted fabric provides incredible stretch and freedom of movement in this mummy-shaped liner and works perfectly with sleeping bags of any shape Sea to Summit Guarantee is offered for the Lifetime of this product Features: - HeiQ Fresh odour control technology helps keep the liner fresh even after extended use