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Reactor Fleece Liner - THERMOLITE

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Our warmest sleeping bag liner+ View tech specs
  • Shape
  • ColourGrey
You can add a maximum of 20 units of this product to your cart.

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

We use climate-neutral shipping with DHL GoGreen.

For orders with a value below 75€ we charge a shipping fee of 4,95€. We do not charge shipping fees for orders with a value over 75€.

All orders received by 12:00 noon on weekdays are usually shipped the same day. Later orders are usually dispatched the following working day.

Delivery time can take up to three working days Germany-wide and up to four working days for orders outside of Germany, and depends on the shipping service provider.

All orders can be returned within 14 days of purchase. However, for the sake of the environment, please make sure to keep returns as low as possible.

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Reactor Fleece Liner - THERMOLITE
Reactor Fleece Liner - THERMOLITE
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.

You have more questions?

Check out our FAQ page HERE and discover even more answers about our products.

Customer Reviews

Based on 33 reviews (Reviews from global Sea to Summit websites) Write a review