Reactor Liner (adds up to 14°F)
BEST USE: Backpacking & Camping
WEIGHT: 8.7 oz | 248 g
LENGTH: 6 ft 10 in | 208 cm
PACKED SIZE: 5.75 x 4 in | 15 x 11 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
The THERMOLITE® Reactor liner is our top selling and lightest thermal sleeping bag liner. It's an excellent cold weather option for those who need additional warmth. The hollow core fibers trap heat and offer extraordinary insulating properties. This is a super stretchy, soft, and comfortable choice with a mummy shape, foot box and a drawcord hood. Compact and lighter weight than fleece, this is a best seller for good reason.
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.
Added WarmthUp to 14°F / 8°C
Best UseBackpacking, Camping
Comes WithUltra-Sil stuff sack
Material(s)Thermolite polyester fabric
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.