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Review Summary
2025-07-05T20:00:00
Used the bag liner for a week camping. Worked great. Definitely recommend your Sleeping Bag Liners. Very roomy.
Glenda C.
2025-05-21T20:00:00
I have a down quilt was getting cold drafts coming in and disrupting my sleep. I actually put the quilt inside the liner and I was super warm
John A.
2025-04-22T20:00:00
Compact. Easy to deploy. Adds loads of warmth for a small footprint. This is a great, inexpensive option to add significant warmth and extend the temperature range of your sleep system. If you're camping in multiple temp ranges, this can allow you to use a lighter weight bag and then use the liner on cold nights. Sea to summit makes awesome kit, this is no exception.
Frostbite
2025-03-08T19:00:00
The mummy shape is very comfortable, and the materials feel high-quality.
Dorit h.
2025-03-08T19:00:00
Soft and comfy
ANTHONY S.
2025-02-13T19:00:00
I was on an upper Grand Canyon river trip during the polar vortex in January, and purchased this liner in anticipation of that, since I only have a 20 degree sleeping bag. This liner did its job and kept me perfectly warm and cozy during the trip!! With the caveat that I also had a puffy blanket; if I hadn't, the liner may not have been quiiite warm enough (it got down to 10 degrees at night, according to my friend who brought a thermometer on the trip). But regardless, I would highly recommend it for cold weather camping! I also really liked the snap-closure arm holes, so I could have my arms free instead of them being mummified in the liner.
Heidi S.
2024-11-11T19:00:00
This was a great addition to my Spark Ultralight sleeping bag to give me a bit of an insulation boost for a cooler weather backpacking trip. For my purpose, this was a much better option vs. buying a warmer sleeping bag. My only complaint is the opening at the bottom. Seriously, who needs that? I certainly have no interest in walking around camp in my sleeping bag liner. There are better ways to keep warm when not in my tent. The opening with the drawcord just adds unnecessary weight, cost and an opening for a draft. Drop the opening, sew it closed and it will be perfect.
Joe Z.
2024-10-28T20:00:00
When temps get low, this liner is great to take the edge off of the cold air. Comfortable fabric. I am pleased with the results. Partner to a zero degree bag, it is exactly what I was looking for
Benjamin A.
2024-10-10T20:00:00
This liner is always with me, if I am not using to stay extra toasty in my bag, I use it as a pad sheet for sleeping on during the hot desert nights. Absolute must have for any serious outdoors person
Alex C.
2024-09-30T20:00:00
Just went on a 3 days camping trip using my traverse IIv -4 sleeping bag and this liner inside. I am always cold, but this liner really warmed up the bag and made it toasty. Waking up to -3 celsius in the morning, I didn't want to get up because it was so nice inside my bag, liner and tent. For me, I will get down booties though as my feet are never warm. Highly recommended and it is light and packs small.
Angela S.
2024-08-15T20:00:00
Light weight and amazing warmth. I ordered this to add the additional warmth and my bag and it has exceeded my expectations!
Andrea D.
2024-08-10T20:00:00
Reactor sleeping bag liners are a must have, not only to protect the sleeping bag but to give added comfort and warmth. The reactor extreme really delivers and its design features, with the arm holes and base draw cord, make it functionally versatile and adaptable over a range of temperatures.
William P.
2024-07-25T20:00:00
Staying toasty on cold nights is critical for a good night sleep for me. The opening at the bottom allows me to have my feet out and still benefit from the extra warmth.
Laura P.
2024-04-30T20:00:00
Love that it's easy to pack, light and super warm. The texture is super soft too. Highly recommend as an extra layer for your sleeping bag! Perfect for super cold camping nights.
Jachunter
2024-04-26T20:00:00
I received this product free, complimentary of influenster, in exchange for an honest review. Super high quality and warm LINER! Better than most actual sleeping bags and only a liner! This has motivated me to purchase a sleeping bag by Summit because of how nice and warm the liner is.
Tkeegz
2024-04-24T20:00:00
Material is soft and durable, easy to bring along on a camping trip. Fits snug in the little bag it comes in. Its like laying in a soft comforting cocoon, I cant wait to use it when I go camping. Its breath-able and yet keeps you warm at the same time.
Zoejanereviews
2024-04-22T20:00:00
Went camping up at Yellowstone national park and this baby arrived in the mail just in time. While my friends were shivering at night and feeling the chill, I was toasty and warm. Also this was super easy just to clip into my pack and didn't have to be a hassle to bring with. Great device and I loved every minute of using it
Andy B.
2024-04-17T20:00:00
Truly impressed with the quality of this liner; perfect for campers and outdoor enthusiasts alike. Super lightweight but also relatively warm, so it'd make a great addition to your camping supplies. Could probably double as a sleeping bag in the summer! Overall, I definitely recommend.
Amandac1137
2024-04-15T20:00:00
This sleeping bag liner packs up very small and is convenient to carry around. It is very lightweight and breathable but the material feels high quality. I didn't have any issue washing it. On its own it is not very warm, which is actually preferable here in a warmer climate, but it would definitely help to insulate in combination with a sleeping bag.
Marcyl7
2023-12-28T19:00:00
Light weight, soft and warm. Should work great as an additional layer in my system.
Kevin
2023-12-27T19:00:00
Cozy without being heavy
Jackie W.
2023-12-12T19:00:00
Increased the warmth of my sleeping bag to get thru the cold fall nights.
Laura
2023-11-04T20:00:00
Small, compact and under 1 pound. Feels nice on the skin. Anxious to try it with my 30 degree down bag.
Scott
2023-10-06T20:00:00
Warm. Soft. Comfortable. Great addition to shoulder season camping
Daniel
2023-09-12T20:00:00
This item kept me warm when temps dropped substantially on an alaska moose hunt
Nicholas
2023-06-01T20:00:00
Fits inside sleeping bag perfect and is super light
Zachary
2023-05-14T20:00:00
My fiancé is always cold when camping. She is cold so often that I started packing two sleeping bags and stuffing them inside each other just for her. It was not the most practical or space saving method so I eventually bought this liner and it solved both problems. Save space and weight because it's so small and adds additional warmth to her bag. The material is very comfortable as well.
Curtis
2023-05-11T20:00:00
This liner is smaller than a soda can which is essential for backpacking. Did not believe this would work at first. Now, I carry it on all cold weather trips. The layer does help keep ya warm! It has also held up well with washes and monthly use.
Jeremy G.
2023-02-04T19:00:00
Bought it for my son that is using it for the first time camping this weekend, hence the only 4 star rating. Seems well made and stitched and appears it should work as advertised. Will update this review after he returns.
Jason S.
2023-01-20T19:00:00
Haven't used it yet, sorry busy currently work ing to be able to pay for the next purchase .
Darryl
Thermolite Pro & EcoMade Polyester
Bio-based HeiQ Fresh Odor Control
Thermal Boost
78" (198cm)
85" (216cm)
85 x 31.5" (216 x 80cm)
Packed: 5.9 x 3 x 4.7" (15 x 7.5 x 12cm)
12.8 oz (364g)
9327868158331
Worked great
By John A.
I have a down quilt was getting cold drafts coming in and disrupting my sleep. I actually put the quilt inside the liner and I was super warm
Great Warm Liner
By Jachunter
Love that it's easy to pack, light and super warm. The texture is super soft too. Highly recommend as an extra layer for your sleeping bag! Perfect for super cold camping nights.
Enhanced Warmth with Infrared-Absorbing Technology
This Sleeping Bag is an essential addition to any cold-weather sleep system, designed to increase warmth and comfort in extreme conditions. Utilizing Thermolite Pro fabric and hollow-core fibers, this liner features infrared-absorbing ceramic pigments that retain and reflect body heat, delivering a thermal boost to your sleeping bag or sleep mat. Whether used as a standalone layer in milder weather or combined with a sleeping bag for extra insulation, it effectively enhances temperature regulation, keeping you warm and comfortable during cold-weather adventures.
Breathable, Moisture-Wicking & Flexible Design
Made from soft, wicking stretch-knit fabric, this mummy-shaped sleeping bag liner provides exceptional comfort and flexibility while maintaining a snug, heat-retaining fit inside any sleeping bag. The moisture-wicking properties help keep you dry, preventing dampness caused by sweat or condensation. Designed for maximum adaptability, the Reactor Extreme liner conforms to different sleep systems, making it an ideal companion for campers, backpackers, and high-altitude explorers who need both warmth and breathability.
Customizable Ventilation & Long-Lasting Freshness
Equipped with a drawcord footbox and adjustable shoulder openings, this liner provides personalized airflow, allowing you to open or close the ventilation points based on your comfort needs. The footbox is designed to integrate seamlessly with the Free-Flow Zip system in select Sea to Summit sleeping bags, enhancing its versatility. Additionally, the HeiQ Fresh odor control technology keeps the liner fresh for extended use, making it perfect for multi-day treks, winter camping, and long-term expeditions. The drawcord footbox also enables mobility, allowing you to walk around camp while staying warm, making it a practical choice for cold mornings and nighttime use.
Technical Features
HEIQ Fresh
Sea to Summit Liners are treated with HeiQ Fresh FFL, a biocide-free, highly effective odor control technology that uses a bio-based Amino Sugar Polymer to neutralize body odor.
Thermolite Pro
Thermolite Pro has engineered hollow fibers like standard Thermolite but with the addition of permanent ceramic pigments that absorb the body's infrared rays and reflect them back to the wearer.
Thermolite Eco Made
The recycled Thermolite EcoMade fibers are made from 100% textile waste, are GRS-certified, and offer the same quality and durable lightweight warmth as their polymer virgin counterparts but with a lower carbon footprint.
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