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Reactor Fleece Liner (adds up to 18°C)

Our warmest sleeping bag liner+ View tech specs
  • Shape
  • ColourGrey

BEST USE: Backpacking & Camping

WEIGHT: 13.4 oz | 379 g

LENGTH: 6 ft 6 in | 200 cm

PACKED SIZE: 9 x 5 in | 22 x 13 cm

Shipping & Returns

Free  express delivery in Australia for orders over $49.99*.

For all other orders under $49.99, we charge a flat fee of $10.00 for delivery in Australia. 

For more details, check out our Shipping Policy.

We do not ship to an address outside of Australia.  

If you are not entirely satisfied with your order, you may be entitled to a refund of the purchase price of the Product. For more details, please check out our Refund Policy.

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Reactor Fleece Liner (adds up to 18°C)
Reactor Fleece Liner (adds up to 18°C)
Description || Reactor Fleece Liner (adds up to 32°F)


The THERMOLITE® Reactor Fleece liner is Sea to Summit’s warmest sleeping bag liner. Add one to your sleeping bag before heading into really cold environments, or use it as a 'stand alone' sleeping bag when the weather is warmer. The core THERMOLITE® fibres have the same hollow structure as a polar bear's fur, which traps a high level of insulating air. Luxuriously soft, the Reactor Fleece is perfect as part of a cold weather sleep system – plus it will help keep your sleeping bag clean.

Design Details

Technical Features


Tech specs

  • Added Warmth
    Up to 32ºF / 18ºC
  • Best Use
    Camping, Winter Camping & Travel
  • Comes With
    Ultra-Sil stuff sack
  • Material(s)
    Thermolite fleece
  • Shape
  • Zip Options
    1/4th length zipper

Frequently Asked questions

Work as a stand-alone sleeping bag?

In many cases, yes. The only factor to be aware of is that the fleece fabric is not windproof.

Add 32°F / 18°C to any sleeping bag?

Not necessarily. There are a lot of factors involved in the thermal performance of a sleep system, starting with the insulation value of your sleeping pad.

Work for backpacking?

It may. The Reactor Fleece is light and small enough for it to be worth carrying for the additional warmth. Weight-conscious performance users may opt for a Spark Liner or Flame Liner.

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