THERMOLITE Reactor Fleece Liner (Adds up to 32°F)

This liner is so warm you can use it in your sleeping bag or on its own


Size Guide

No Online Retailers Stocking Current Selection


The THERMOLITE® Reactor™ Fleece sleeping bag liner is a luxuriously soft and super warm liner that can bump up the warmth of your sleeping bag considerably. It can also be used as a stand-alone sleeping bag in warmer climates and has a quarter length zipper to control temperature and allows the user to get in and out of easily. The hollow core fibers that make up this fabric trap heat effectively, keeping you toasty warm.  If you're looking for a high warmth to weight ratio or a lightweight summer bag, this is an ideal choice.

Learn more about which liner is right for you HERE


Packed Size Comparison

A little larger than a wide mouth water bottle (BPA free of course)


14.8 oz ≈ Lighter than a roll of paper towels


Add a full season rating to your sleeping bag


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


  • Adds up to 32°F / 18°C of warmth to a sleeping bag
  • Technical mummy shape with one hand, easy to operate, drawstring hood
  • Quarter zip makes it easy to get in and out
  • Can be used as a stand-alone sleeping bag in warmer temperatures
  • Packs into its own Ultra-Sil™ stuff sack