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4.6 15

Sea to Summit

Thermolite Reactor Liner

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If your sleeping system needs some extra warmth, then the Thermolite Reactor Liner from Sea to Summit will add up to 8°C and help keep your sleeping bag clean.

This liner is made from Thermolite hollow core fibres which traps heat and has excellent insulating properties while being lighter than fleece. Thermolite is also soft and super stretchy so it’s really comfortable. The design of this liner is optimised for warmth, as it has a mummy shape, footbox and a drawcord hood. It will add up to 8°C of warmth to a sleeping bag, or it can be used on its own as the ideal warm-weather bag. The Thermolite Reactor also comes with a stuff sack included, so you can store it away neatly when not in use.

Prolong the life of your sleeping bag, and add extra warmth with the Thermolite Reactor Liner from Sea to Summit.

  • Adds up to 8°C of warmth to a sleeping bag
  • Made of ultra-lightweight Thermolite fibre
  • Mummy shape with a box foot
  • More compact and warmer for its weight than fleece liners
  • Thin drawcord with tiny cord-lock around the hood
  • Packs into its own lightweight sack
  • Use inside a sleeping bag for extra warmth or as a stand-alone bag in warm weather
Snowys Code:
Supplier Code:
Max. User Height:
210 cm
Internal Girth:
180 cm
External Dimensions:
210L x 90W cm
Packed Dimensions:
17L x 11W x 11H cm
0.248 Kg
Suggested Use:
Hiking | Trekking
Limited Lifetime

(15 reviews)
4.6 15
5 stars
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1 star
Oct 04 2018

lovely and cosy

I'm so pleased I got this, I was much more comfortable in my sleeping back with this. I use a black wolf bag rated to -3 and was sleeping in a hut with outdoor temp around 6.

- Hobart, TAS
Sep 17 2018

Toasty Warm

I have no doubt that this adds 8 degrees when used properly (ie hood around head etc). I am a cold sleeper, slept in this at approx -5 degrees in a tapered fit sleeping bag and felt like I was sleeping like the prior night's 5 degrees. Quick drying too. May consider cutting a hole in the bottom for feet to pop out of sleeping bag in the future.

- Newcastle, NSW
Aug 08 2018

Thermolite Reactor Liner

Excellent. Super stretchy and comfortable to sleep in. Warm and feels great.

- 2484
Jul 23 2018

Great addition

This makes a +10 bag much more comfortable in colder conditions.
ps: great service from Snowys as well.

- Frenchs Forest, NSW
Jun 04 2018

Love it

Makes a difference. Very lightweight and worth for the added comfort. Streches a lot so doesn’t restrain the toss and turning.

- Queenscliff, NSW
May 07 2018


larger than i thought it would be, but nice and soft and kept me warm,

Apr 26 2018

Liked it

Used it for 5 days camping in an alpine area and I was warm enough in a down bag. It was comfortable against your skin and you didn't get tangled in it. Plenty of length and width. Downside is if you are into light weight camping it is heavier than silk but the added warmth would be worth it.

- Richmond Vic
Mar 18 2018

Love This

This is lightweight but warm. Can be used on its own when it’s mild weather and is excellent inside my sleeping bag on cold nights. It’s soft and stretchy and is really comfortable to sleep in. Lots of room in it. Highly recommended.

- Rockingham, WA
Feb 04 2018


Great to use as a sleeping bag when it's hot, and keeps you toasty inside your sleeping bag when it's cold out. I was skeptical but it works. And snowys is the place to buy it price wise.

- Melbourne
Jan 25 2018

Perfect for hot nights

Have used it once, and it was a very hot night. I started out using it as a top sheet just over my torso, and then as the temp dropped through the night, got inside of it. I love that it's so stretchy my legs can still move freely.

- Newcastle, NSW
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how tapered is the long liner1 answer

I don't want to be too raestricted when I insert into the liner insert around my feet. Will I regret ordering the tapered liner ?

- Adelaide(1 year ago)

G'day Bryan,

The Sea to Summit Thermolite Reactor Liner tapers about 10cm from the shoulders. The benefit of the liner is that the fabric is quite stretchy. While I can't speak for your opinion, common feedback is that the stretchy fabric makes the liner feel un-restrictive around the feet.

- Snowys(1 year ago)

Reactor Extreme?1 answer

Hi there, do you sell the Reactor Extreme liner as well? Thank you.

- Sydney(2 years ago)
G'day CH - We sure do. For some reason we haven't uploaded it online yet, but I see it has the Snowys code of #38184, and we do have a couple in stock (as of when I post this). To order one, give us a bell on 1300 914 007. Cheers, Paul
- Snowys(2 years ago)

It gets cold here, real cold.1 answer

Added to the roman mummy -5 deg sleeping bag, will it keep you warm and toasty in temps of around -8?

- BUNDARRA, NSW(2 years ago)
Hi again Ric. There are so many variables here that it's hard to say for sure. Not knowing exactly which sleeping bag you have, it's likely that the -5 rating is the lower limit, so the comfort rating is probably around +1 or +2. Even with this liner, on a -8 degree night I think it would still be too cold. It depends a lot on the person - whether you are a hot or cold sleeper. A good insulated sleeping mat will help a lot, and of course a set of thermals. For me personally, I would be getting a warmer sleeping bag if I was expecting those temperatures while camping. I hope this helps, please give us a call if you would like to discuss further. 1300 914 007.
- Snowys(2 years ago)

How do you wash it?1 answer

Is it drip dry. do you spin it out,?

- BUNDARRA, NSW(2 years ago)
Hi Ric, this liner is machine washable and will be fine for a normal spin cycle, but not suitable for the dryer.
- Snowys(2 years ago)
Heads up! Our store in Brendale (QLD) doesn’t have footwear available for fittings. If you order online, your footwear will be sent from SA... quick-smart!
Heads up! Our store in Brendale (QLD) doesn’t have footwear available for fittings. If you order online, your footwear will be sent from SA... quick-smart!
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