Sea to Summit Reactor Fleeceweight Liner

Your secret weapon against freezing nights, without the weight penalty. This Sea to Summit liner harnesses Thermolite® Fleece to deliver serious warmth while staying compact enough to slip into any pack. The stretchy fabric moves with you, armholes keep your shoulders free, and whether you're a restless sleeper or a still one, you'll stay comfortable. Snap it into compatible Sea to Summit sleeping bags for a locked-in fit, or layer it solo inside your existing bag. Machine washable and ready for adventure.

Max User Length: 170cm (Short). 185cm (Regular). 198cm (Long).

Using Thermolite® hollow-core fibres in a grid-fleece construction, the Fleeceweight traps and reflects body heat to noticeably enhance your sleep system’s performance, adding up to 8°C of warmth with minimal added weight.

The liner is quick-drying and easy to clean, with HeiQ Fresh odour control to stay fresher on extended trips. It also helps extend your sleeping bag’s lifespan by reducing the need for frequent washing, preserving loft and long-term performance.

Best Use For: Backpacking, Camping & Winter Camping.

Features

• Freedom to Move: Thermolite® Fleece fabric and armholes allow unrestricted movement in any sleep position.
  
• Thermal Boost: Grid-fleece with hollow-core fibres traps and reflects heat—adds up to 8°C warmth.
  
• Bag Compatibility: Fits any sleeping bag; snaps into Sea to Summit bags for secure placement and easy entry/exit.
  
• Extend Bag Lifespan: Reduces washing frequency to maintain insulation loft and long-term performance.
  
• Easy to Clean: Quick-drying fabric with HeiQ Fresh odour control stays fresher on multi-day trips.
  
• Ideal for cold-weather backpacking, hut trips, and winter bivvies where extra warmth matters.

Specification

• Shape: Mummy
• Added up to 8°C Warmth
• User Length: 170cm (Short). 185cm (Regular). 198cm (Long).
• Weight: 365g (Short). 400g (Regular). 420g (Long).
• Stuff sack included
• Materials: Thermolite Pro & Thermolite EcoMade