
Reactor Extreme Liner (adds up to 25°F)
Highlights
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
Shipping & Returns
Our warehouse is actively shipping orders from 8am to 1pm MST Monday through Friday. Most orders ship in one business day, but the transit time can take up to 7 days, depending on your distance from Boulder, Colorado.
2nd Day and Next Day Air orders will ship same day if placed by 1pm MST, Monday-Friday (except holidays).
All orders are eligible for fast and easy returns within 60 days of purchase.
For more details, please check out our Help Center
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Description
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 fibers 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.

Design Details
Technical Features

The Reactor Series Sleeping bag liners, the Venture, Traverse and Basecamp synthetic Sleeping Bags and the foot boxes of the Women’s Altitude and Journey down Sleeping Bags use hollow core THERMOLITE® fiber to add warmth. These fibers trap extra air for insulation (just like the hollow-cores of polar bear or caribou fur). In the liners, the knitted THERMOLITE® fabric is soft and stretchy and comes in three different weights: 80g/m² fabric used in the Reactor and the underside of the Compact Plus liners; a 110g/m² fabric which is used in the Extreme, and the core and foot box of the Compact Plus liner; and the Fleece, the warmest of all the fabrics. THERMOLITE® is also used in the Air Sprung Cell sleeping mats.
Tech specs
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Added WarmthUp to 25°F / 14°C
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Best UseBackpacking, Camping & Winter Camping
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Comes WithUltra-Sil stuff sack
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Material(s)Thermolite polyester fabric
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ShapeMummy
Regular Mummy | Long Mummy |
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Frequently Asked questions
Suitable for use with a rectangular / wide sleeping bag?
The knitted fabric of the Reactor is so stretchy that you won’t feel the shape of the liner at all.
Equipped with a zipper?
No - to keep this sleeping bag liners at a minimal weight and packed size we did not include a zipper.
Washed in a washing machine?
Yes - you can wash your liner in a washing machine with normal supermarket laundry ‘soap’ and dry it in a dryer, using cool or low heat. Fabric softeners will reduce wicking performance of the fabric.