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Sea to Summit Thermolite Reactor Liner

Review Last Updated: March 19, 2020


Today we'll be reviewing the Sea to Summit Thermolite Reactor Liner.

Our reviews are based on in-depth research and product analysis. Let's dive in!


  • Mummy shape with a box foot
  • Adds up to 25F warmth to sleeping bag
  • Packs into its own Ultra-Sil stuff pack
  • Thermolite construction throughout


  • Price might turn-off some customers
  • Can be too hot for warmer temperatures

Sea to Summit Thermolite Reactor Liner Product Review

The Thermolite Reactor Liner is the warmest backpacking knit sleeping bag that Sea To Summit offers, and it has made quite an impression with survivalists.

Not only does Sea To Summit provide an extreme warmth edition, but it also has versions that excel in lightweight and liners that entertain various climates.

This edition, however, is highly recommended for colder temperatures and for when you need additional protection from the unknown.

Sea To Summit compare the hollow fiber thread used to the hollow fur of a polar bear because of its ability to trap heat effectively.

Depending on your atmosphere and sleep conditions, this liner can increase your sleeping bag warmth by up to 25F.

This mummy-shaped liner with a box foot uses hollow-core Thermolite fiber and will add warmth and comfort to your outdoor endeavor.

The liner ideally packs down to a small size into its sack and weighs just 14 ounces, which won’t burden your back or clutter your pack.

It falls on the pricier side of the spectrum, but will no doubt be a great addition to your sleeping bags, especially on the colder nights, and will be an excellent long-term investment.

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