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This Mummy-Shaped sleeping bag liner increases sleeping bag performance by up to 11ºC. It's incredibly warm for its weight and still maintains a high level of breathability.
This Mummy-Shaped sleeping bag liner increases sleeping bag performance by up to 11ºC. It's incredibly warm for its weight and still maintains a high level of breathability.
Sea to Summit

Sea To Summit Thermolite Reactor Compact Plus Sleeping Bag Liner Red

£49.50  £55.00  10% off
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Pre-Launch

With Pre-Launch, the date when we expect to receive the product ourselves is still a little too hazy to be confident in accepting Pre-Orders.

So, instead, you can submit your email address against the item you are interested in and we will email you as soon as stock arrives on the system.

Estimated Delivery & Collection Dates

Estimated Delivery & Collection Dates are given on Pre-Order and Pre-Launch products. They are for indication purposes only and can change at any time without notice.

The dates we provide are based on indications given by our suppliers. Whenever we get updated information from our suppliers we will endeavour to update the Estimated Delivery & Collection Dates provided on product pages.

We estimate this will be ready for despatch to you or collection via Click & Collect on the Undetermined

Sea To Summit Thermolite Reactor Compact Plus Sleeping Bag Liner Red Information

Season : 2020W R

Brand : Sea to Summit

Code : AREACTPL-ONE

This Mummy-Shaped sleeping bag liner increases sleeping bag performance by up to 11ºC. It's incredibly warm for its weight and still maintains a high level of breathability. A must-have for cool weather adventures and travelling.

The Reactors impressive warmth to weight ratio comes from Thermolite fabric. The Reactor liner uses two weights of Thermolite fabric - 80 g/m² with 110g/m² panels in the in the core and foot box areas for extra warmth. Thermolite uses a hollow core fibre construction - these hollow cores trap warm air for greater insulation whilst wicking away moisture from your body and allowing it to escape, meaning you'll be comfortable all night long.

The Reactor will add up to 11ºC of warmth to your sleeping bag for only an extra 263g of weight. Alternatively, it works well on its own as an extra layer when hiking from hut to hut in the summer. 

  • Adds up to 11ºC of warmth to your sleeping bag
  • Lightweight
  • Packable
  • First dual fabric sleeping bag liner
  • 110g/m2 Thermolite panels in core body and foot areas
  • Mummy shape with a box foot
  • Drawcord hood with mini cord lock
  • Packs into its own Ultra-Sil stuff sack

How warm a sleeping bag do you really need? We’ve tried to help you by grouping our sleeping bags by their recognised comfort ratings. These are the ratings supplied by the brands that indicate the temperature at which you will remain comfortable whilst sleeping on a good insulated sleep mat. After all, comfortable is what you want to be when it’s cold and wet outside and you’re all tucked up in your nice warm sleeping bag.

We always recommend that you choose your bag according to the coldest conditions you will experience; you can always unzip a bag if it is too warm, but trying to sleep when you’re too cold is just miserable. Bear in mind that that we are all individuals and we all feel the cold differently, and that our own resistance will fluctuate depending a whole load of factors including how much we have eaten, whether we have consumed alcohol, whether we need a wee or what kind of mood we are in!

Sleeping bags do not generate heat they only trap the heat we produce so it is vital that you get into your bag when you are giving off warmth, don’t go to bed when you are cold, have a hot meal or a hot drink or do some brisk exercise to get you nicely warmed up.

Traditionally sleeping bag manufacturers provided their own temperature ratings based on their experience, the products intended end use and the perceived environment. But each brand tested their bags in different ways and it was hard to find a fair comparison between models. So, in 2005 a European standard for sleeping bag temperature ratings, EN 13537, was introduced to give consumers a comparable guide to sleeping bag performance across a range of brands and models. The ratings have four different temperature ratings to give you an indication of the bags performance.

Upper limit: This is the highest temperature at which an average male should experience a comfortable night’s sleep.

Comfort: This is the temperature at which an average female should experience a comfortable night’s sleep. On average women sleep colder than men so this rating is some degrees above the ‘comfort lower limit’ for a man.

Comfort lower limit:  This is the lowest temperature at which an average male should experience a comfortable night’s sleep whilst lying in a curled-up body position. This used to be known as the comfort rating.

Extreme: This is a survival rating where the user is likely to suffer health damage such as Hypothermia. It should be treated with the utmost caution and not be relied on for general use.

However, the EN 13537 European Standard does not apply to down filled sleeping bags with a fill weight of more than 800g; for those bags you will have to rely on the manufacturer's experience and technical expertise, which is often more accurate!

Most reputable brands still use their own rating system alongside EN 13537, for instance the M.E “Good Night’s Sleep” and Rab’s “Sleep Limit”. These ratings are often the most accurate guide to the overall performance of a bag being used by an average outdoor enthusiast. They are based on years of expedition heritage, field trials, technological experience, and constant feedback.

But please bear in mind that all ratings are only a guide and, as mentioned earlier, there are a huge range of factors that can affect your comfort, if you are just not sure it is always wise to go for a warmer model.

The biggest difference you can make to your overall comfort is to use an efficiently insulated sleeping mat. Once you get inside your sleeping bag you instantly compress all the filling beneath you, greatly reducing its efficiency. The use of a quality sleep mat will ensure you are properly insulated from the cold ground and you will of course be a lot more comfortable. Your sleeping bag is only as good as the mat that’s beneath it; we recommend EXPED, ThermaRest or Multimat sleeping mats for comfort and insulation.

Technical Information
Length/Width: 183 x 92 cm
Suitability: Cool Weather
Weight: 263 g
Sizing Information
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