Reactor_Scale and temperature range _ warmth
Description || Reactor Extreme Liner (adds up to 25°F)

Reactor Extreme Liner (adds up to 15°C)

Rs. 7,949.00
Rs. 7,949.00

Perfect for cold weather backpacking

+ View tech specs
Size: Long
Shape: Mummy
Subtotal: Rs. 7,949.00

BEST USE: Backpacking & Camping

WEIGHT: 14 oz | 399 g

LENGTH: 6 ft 10 in | 210 cm

PACKED SIZE: 6.5 x 4.5 in | 17 x 11.5 cm

Reactor Extreme Liner (adds up to 15°C)

Reactor Extreme Liner (adds up to 15°C)

Rs. 7,949.00

Reactor Extreme Liner (adds up to 15°C)

Rs. 7,949.00
Size: Long
Shape: Mummy


The THERMOLITE® Reactor Extreme liner is Sea to Summit’s warmest knitted sleeping bag liner. If your adventures take you to colder climates, the Reactor Extreme will add plenty of warmth to a sleeping bag. Plus in warmer weather, it can be used as a ‘stand alone’ sleeping bag. The hollow core fibres of the THERMOLITE® fabric work like a polar bear's fur and, along with the knitted structure, trap plenty of insulating air. Super soft and amazingly stretchy, the Reactor Extreme uses a heavier version of THERMOLITE®  to provide extra warmth for an incredibly comfortable night’s sleep. Use one to build your cooler-weather sleep system and to help keep your sleeping bag clean too.


  • 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.

The Reactor Extreme is Perfect For¦

  • Backpackers whose sleep system will be used in colder climates
  • Campers whose sleeping bags don't keep them warm a the advertised temperature
  • Very warm-weather campers who don't need a full sleeping bag
  • Campers or backpackers looking to extend the performance of a (perhaps order) sleeping bag into shoulder seasons


  • Added Warmth
    Up to 25°F / 14°C
  • Best Use
    Backpacking, Camping & Winter Camping
  • Comes With
    Ultra-Sil stuff sack
  • Material(s)
    Thermolite polyester fabric
  • Shape
Regular MummyLong Mummy
Compressed Volume1.5 Liters1.5 Liters
Dimensions 208 cm 235 x 90cm
Packed Size 17 x 11.5 cm 17 x 11.5 cm
Packed Volume1.75 L1.75 L
Weight 399 g 422g



Frequently Asked questions

Does this sleeping bag liner fit regular and wide sleeping bags?

This liner is made with durable stretch fabric so it can fit in any sleeping bag shape and you won't even notice.

Does the sleeping bag liner have a zipper?

No. In order to keep this sleeping bag liner at a minimal weight and packed size we did not include a zipper.

Is the sleeping bag liner machine-washable?

Yes! This sleeping bag liner is machine-washable for ease and convenience. You can wash your liner with laundry detergent and machine dry, using cool or low heat. Steer clear of fabric softeners, though, since they tend to reduce wicking performance of the fabric. 

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