Reactor Fleeceweight Sleeping Bag Liner
SIZE
Reactor Fleeceweight Sleeping Bag Liner
REG
1651 Chemin de l'Industrie
1651 Chemin de l'Industrie
Beloeil QC J3G 6S8
Canada
Sea to Summit Reactor Fleeceweight Sleeping Bag Liner
The warmest liner in the Reactor series, designed to increase sleep system warmth, improve comfort, and extend the usable temperature range of your sleeping bag in cold conditions.
Cold-weather backpacking
Thermal Liner
Up to 8°C / 14°F
Thermolite® + Grid Fleece
Built for cold-weather backpacking, ski touring, and even stand-alone summer use, the Reactor Fleeceweight combines Thermolite® hollow-core fibers with grid fleece to trap and reflect body heat while maintaining freedom of movement and simple field care.
Product Overview
The Reactor Fleeceweight is designed for users who need the highest thermal boost in the Reactor range. The stretch fleece construction, ergonomic hood, and shaped arm openings improve comfort and mobility, while helping the liner work effectively inside a sleeping bag or on its own in warmer conditions.
This is a strong option for winter camping, layered sleep systems, expedition kits, and users who want added warmth without immediately stepping up to a heavier sleeping bag.
Key Features
- Warmest option in the Reactor liner range
- Thermolite® hollow-core fibers and grid fleece for thermal efficiency
- Adds up to 8°C / 14°F to a compatible sleep system
- Stretch-knit construction for comfort and mobility
- Shaped arm openings for unrestricted movement
- Technical hood for better warmth retention
- HeiQ Fresh odor control treatment
- Snap connectors compatible with Sea to Summit sleeping bags
- Machine washable and quick drying
- Can be used on its own in warm-weather conditions
Ideal Applications
- Cold-weather backpacking
- Ski touring and winter camp systems
- Layered expedition sleep setups
- Adding warmth to existing sleeping bags
- Reducing sleeping bag wash frequency
- Users prioritizing maximum warmth in a liner format
Technical Specifications
| Specification | Regular | Long |
|---|---|---|
| Best Use | Cold-weather backpacking, Ski touring, Stand-alone summer use | Cold-weather backpacking, Ski touring, Stand-alone summer use |
| Type | Thermal Liner | Thermal Liner |
| Material | 100% Post-Consumer Recycled Polyester; Stuff Sack: 100% Polyester | 100% Post-Consumer Recycled Polyester; Stuff Sack: 100% Polyester |
| Weight | 14.1 oz / 400 g | 15.2 oz / 430 g |
| Dimensions | 76.0 x 31.5 in / 193 x 80 cm | 81.1 x 31.5 in / 206 x 80 cm |
| Packed Size | 5.9 x 9.8 x 5.9 in / 15 x 25 x 15 cm | 5.9 x 9.8 x 5.9 in / 15 x 25 x 15 cm |
| Warmth Increase | Up to 8°C / 14°F | Up to 8°C / 14°F |
| Construction | Thermolite® hollow-core fibers + grid fleece | Thermolite® hollow-core fibers + grid fleece |
Why Choose the Reactor Fleeceweight
For users needing the strongest thermal gain in a liner format, the Reactor Fleeceweight sits at the top of the Reactor range. It is better suited to colder conditions and larger winter packs than minimalist ultralight use, making it a practical addition to serious cold-weather sleep systems.
It also helps protect the interior of your sleeping bag from dirt, sweat, and repeated wash cycles, which can help preserve loft over time.
