Sea to Summit

Sea To Summit Thermolite Reactor Extreme Mummy Sleeping Bag Liner

Regular price £43.99
The THERMOLITE® Reactor Extreme liner is Sea to Summit's warmest - a game-changer in cooler climates! Not only does it amplify your sleeping bag's warmth, but it can also be used as a standalone bag for those warmer nights. Depend on the hollow core fibres and knitted structure to deliver the insulation of a polar bear's fur, plus an extra-cosy sleep experience thanks to the heavier fabric version of THERMOLITE®. Treat yourself to more comfort and cleanliness - use the Reactor Extreme to build your cooler-weather sleep system!

  • Traps insulating air to increase warmth of a sleeping bag by up to 25°F / 15°C
  • Stretchy, Thermolite® fabric is incredibly comfortable.
  • 110g/m² fabric is warmer than the 80g/m² Thermolite® used in the standard Reactor.
  • Technical mummy-shape with drawstring hood.
  • Easy care – machine wash with no special soap needed. Avoid fabric softeners and dryer sheets.
  • Keeps sleeping bag clean.
  • Packs into its own Ultra-Sil stuff sack.
  • Length/Width: 210 x 90 cm
  • Weight: 399g

Please Note: We are unable to accept returns of sleeping bag liners for obvious hygiene reasons unless faulty.
All details are in the listing, so please do NOT buy these if you are unsure of suitability.

    Customer Reviews

    Based on 7 reviews
    Julia Richardson
    A Great piece of Kit - Sea to Summit Thermolite Reactor Extreme Mummy Sleeping Bag Liner

    I used the Sea To Summit Thermolite Reactor Extreme Mummy Sleeping Bag Liner for the first time at the weekend, in conjunction with a down sleeping bag and it worked really well. I will be using it for bike-packing and camping so the pack-down-size and weight were important as this needs to be stuffed into bike bags. It's a very nice bit of kit and worked well even though it wasn't particularly cold and the price was equally good too, with the added efficiency of freshairjunkie and Royal Mail.


    Great product

    Kevin Cowell
    Great Value and Super Fast Delivery

    Top store with great prices and super fast delivery, many thanks.


    Easy ordering system & fast and efficient delivery.

    Dale Sinclair
    Great service with reasonable prices!

    Absolutely no hesitation in recommending this retailer - good prices and quick delivery, what’s no to like!