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The Reactor Fleece Liner is built from hollow-core Thermolite® Pro fibers used in a grid pattern to deliver Sea to Summit's warmest sleeping bag liner and the core of any quality cold-weather sleep system.
You can regulate your temperature using the shoulder zippers and drawcord footbox, which also align perfectly with the Free Flow-Zip system of Sea to Summit sleeping bags. The versatile Reactor Fleece Liner delivers comfort across multiple seasons or can even be used as a stand-alone sleeping bag in warm weather. Additionally, the drawcord footbox offers plenty of ventilation and the versatility of walking around camp while still wearing your liner if needed.