THERMOLITE Reactor Liner

Cold in your sleeping bag? Grab a Reactor liner


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The THERMOLITE® Reactor™ liner is our top seller in the sleeping bag liner range. It's an excellent cold weather option for those who need additional warmth. The hollow core fibers trap heat and offer extraordinary insulating properties. This is a super stretchy, soft, and comfortable choice with a mummy shape, foot box and a drawcord hood. Compact and lighter weight than fleece, this is a best seller for good reason.

Learn more about which liner is right for you HERE


Packed Size Comparison

Similar to a small foam football


8.7 oz ≈ Two sticks of butter


Adds up to 14°F to the temperature range of your sleeping bag


Easy to wash and helps to keep your down bag cleaner for longer


  • Adds up to 14°F / 8°C of warmth to a sleeping bag
  • Lighter weight, more packable than fleece
  • Mummy shape with a box foot
  • Drawcord hood with mini cord lock
  • Packs into its own Ultra-Sil™ stuff sack