What Our Gearhead® Experts Are Saying:"I started bringing the Reactor Extreme Mummy Drawcord Sleeping Bag Liner on trips where I knew conditions would push the lower limit of my quilt, and it has completely changed the way I build my sleep system for shoulder-season trips. The Thermolite Pro fabric reflects body heat back in a way you actually feel, and the stretch knit is so comfortable against the skin that I barely notice it is there until I realize how warm I am."There is a particular kind of cold that settles into a campsite around 2 am, the kind that makes you question every gear decision you made before you left the trailhead. Sea to Summit built the Reactor Extreme Mummy Drawcord Sleeping Bag Liner for exactly that moment, adding a meaningful layer of warmth to any sleep system without asking you to carry a heavier bag to get it.The key is Thermolite Pro fabric, a hollow-core knitted construction woven with infrared-absorbing ceramic pigments that catch your body heat and reflect it back rather than letting it escape. The result is a liner that actively works to keep you warm rather than just adding a passive layer of insulation. The stretch knit moves with your body through the night and fits inside any sleeping bag shape without bunching or binding, while the drawcord footbox and shoulder openings let you dial ventilation up or down as the temperature shifts. When camp chores call before the sun comes up, the drawcord closure means you can step outside still wearing the liner, already warm before the day begins.
Material: EcoMade polyester, Thermolite Pro tech, HeiQ Fresh odor-control tech;
Shape: mummy;
Stuff Sack: included ;
Stuff Size: 6 x 3 x 5in;
Dimensions: [compact] 78in x 21.6 - 31.5in, [standard] 85 x 21.6 - 31.5in ;
Claimed Weight: [compact] 12.1oz, [standard] 12.8oz;
Activity: camping ;
Manufacturer Warranty: lifetime ;
storecredits: 0.0;
Style Variants
Available Colors: Spicy Orange
Size Reference for Sea to Summit Sleeping Bag Liner
Available Sizes: Spicy Orange, Compact, Standard
