Find Your Store
Home Page

Cart, contains 0 items

When autocomplete results are available use up and down arrows to review and enter to select. Touch device users, explore by touch or with swipe gestures.
Expert Help
Earn Rewards

Sea To Summit
Thermolite Reactor Fleece Liner

4.62 out of 5 stars
50 Reviews

Out of Stock

Don't worry though, we have a lot more Sleeping Bag Liners in stock than that.

Shop Similar Products

Thermolite Reactor Fleece Liner

Sea To Summit's Reactor Fleece Liner warms up sleeping bags on winter camping trips, and keeps you cozy on its own during warm summer backpacking adventures. Thermolite fleece retains your body heat to add a surprising amount of warmth for how light and compact the liner is. Sea To Summit added a quarter-zip for easy entry, and the drawstring hood stays snug overhead to keep your ears cozy.

Details

  • Thermolite fleece liner
  • Quarter-zip
  • Drawstring hood
  • Item #STS002S
Material
Thermolite
Shape
mummy
Claimed Weight
14.8oz
Manufacturer Warranty
lifetime

Overall Rating

4.5 based on 50 ratings

Review Summary

1 Stars - 1 reviews
2 Stars - 1 reviews
3 Stars - 2 reviews
4 Stars - 8 reviews
5 Stars - 38 reviews

Fits True To Size

Screen reader users: the following list provides a visual scale to illustrate the product fit. Please refer to the heading above for the fit type in text.
Runs smallTrue to sizeRuns large

What do you think about this product?

View

Selecting an option will reload the available reviews on the page
4 out of 5 stars

February 12, 2024

Comfy

[This review was collected as part of a promotion.] Satisfied with the look & feel so far. The ultimate test will be when I use it in Yellowstone at the beginning of May.

Stacey C.
Sea to Summit

Originally reviewed on Sea to Summit

5 out of 5 stars

December 7, 2023

The Reactor Fleece Liner kept

[This review was collected as part of a promotion.] The Reactor Fleece Liner kept me warm and toasty in a tent during Patagonias shoulder season. Well worth the money!

Debra D.
Sea to Summit

Originally reviewed on Sea to Summit

5 out of 5 stars

November 30, 2023

Warmer but not 32' warmer for this cold sleeper

[This review was collected as part of a promotion.] I intentionally took a sleeping bag not warm enough for my camping trip to test the liner. The liner was soft and I liked the zipper and hood. It ended up colder than forecast so I was thankful for a back up down blanket. The liner did make the sleeping bag warmer, but being a cold sleeper, it did not increase the warmth by 32', perhaps 10' for me. I still love the liner and will simply add it to a better rated bag next time.

Sherry Z.
Sea to Summit

Originally reviewed on Sea to Summit

4 out of 5 stars

November 24, 2023

Very warm, nice and soft, but legs felt restricted

Used this for the first time last week in Fall Creek Falls and the low overnight was about 31 or so. Paired with my new BA Anthracite 20 bag (also first time use). I do NOT like the cold and I consider lows in the 30s as the absolute lowest overnight temp I would choose to camp in. I was pleasantly toasty all night - never too hot - felt great! The liner is soft. My only complaint is that my legs and feet felt very restricted. The second night was around 45 or so degrees so I used the bag alone without the liner and discovered the restriction I felt the first night was due to the liner - not the mummy shaped sleeping bag. Perhaps some kind of stretchy material could be added to this liner from the hips down - even better if that fabric was “slick”. If that could be woven into the existing fabric to retain the warmth but allow more freedom of movement without it ‘grabbing’ onto your legs/PJ bottoms/socks that would be truly amazing. Giving this four stars overall due to the restriction I felt (others may not) - but would give it five stars for warmth without burning me up.

Tracy
Sea to Summit

Originally reviewed on Sea to Summit

5 out of 5 stars

November 22, 2023

Reactor Fleece Liner (adds up to 32°F)

The Reactor Fleece liner is very nice. I used it as a winter sleeping bag when I camped down in the USVI. It kept me warm and cozy. Mind you, I still needed a sweater, thermals and socks. I recently gave it to my son for his work related National Park trip and I am now purchasing another one. The size, comfort and packability fit the bill!

Pattie
Sea to Summit

Originally reviewed on Sea to Summit

5 out of 5 stars

November 14, 2023

The Sleeping Bag Season Extender I Needed

[This review was collected as part of a promotion.] Huge huge fan of this liner. I have a three-season sleeping bag, but in the shoulder seasons I find myself needing a lot of extra layers and running colder. This liner totally changed the game for me! Took my sleeping bag from doable to super warm on a November camping trip, and allowed me to ditch sleeping with a puffy/hat/million layers of clothing for a much better sleep.

Natalie M.
Sea to Summit

Originally reviewed on Sea to Summit

5 out of 5 stars

November 9, 2023

Karen H

We used the Reactor Compact Plus on our hunting trip this October and was so blessed but having it with us. It rained and rained we got soaked. The outside of our sleeping bags were wet as well as our tent. It’s was around 35 degrees and getting late. We put the Reactor into our sleeping bags and stayed warm all night.

Karen H.
Sea to Summit

Originally reviewed on Sea to Summit

5 out of 5 stars

October 6, 2023

Warm and soft

[This review was collected as part of a promotion.] Warm, lightweight and soft… perfect for camping at Yellowstone!

Cynthia S.
Sea to Summit

Originally reviewed on Sea to Summit

5 out of 5 stars

August 28, 2023

Worth It

An indispensable part of my kit! I take it with me on every overnight campout, no matter the season. On hot nights, it works well on its own as a sleeping bag. On cold nights, it adds a layer of warmth to my sleeping bag. It's useful to think of it like a layer and not as a magic bullet against the cold - on very cold nights, you will probably still need your wool underwear and down or fleece jackets. It also acts like a much-easier-to-clean pillowcase for the inside of my down sleeping bag.

Patricia O.
Sea to Summit

Originally reviewed on Sea to Summit

2 out of 5 stars

August 14, 2023

Disappointed quickly

Good product but the cinch knot broke on only the 2nd or third use Reducing significantly its ability to trap heat thus match its 18C claims

Ronan B.
Sea to Summit

Originally reviewed on Sea to Summit