Rust sleeping bag liner on a white background

Person wearing a rust-colored liner over a light gray long-sleeve shirt on a white background

Red sleeping bag liner with 'Sea to Summit' branding on a white background

Close-up of a rust-colored jacket with white drawstrings and zipper on a white background

Close-up of rust-colored fabric with visible texture

Sea to Summit Reactor Fleeceweight Sleeping Bag Liner

Sea to Summit

$124.00

Length:

Short Regular Long

Variant

Features

Boosts sleep system warmth – The Reactor Fleeceweight uses Thermolite hollow-core fibres and grid fleece to trap heat with minimal added weight
Freedom to move – Stretch-knit construction with shaped arm openings allows natural, unrestricted movement throughout the night
Technical shape with hood – An ergonomic cut and fitted hood maximise warmth and comfort without extra bulk
Stay fresher for longer – HeiQ Fresh odour control helps keep the liner feeling clean on extended trips
Seamless sleep system integration – Shoulder snap connectors pair easily with Sea to Summit sleeping bags for quick, hassle-free entry and exit
Easy to keep clean – Machine washable design simplifies care while reducing wear on your sleeping bag
Lower-impact materials – Made with certified recycled fibres and bluesign APPROVED materials to minimise environmental impact
Versatile use – Can be used on its own as a lightweight sleeping bag in warm-weather conditions

Specifications

Weight

S: 365g
R: 400g
L: 420g

Certification

RCS - 1114661

Dimensions

Short: 80 x 178cm
Regular: 80 x 193cm
Long: 80 x 198cm

Ideal for

Cold-weather backpacking, Ski touring, (Stand-alone) summer use

Packed dimensions

15 x 15 x 25cm

Recommended user height

S: 170cm
R: 183cm
L 198cm

Sea to Summit Reactor Fleeceweight Sleeping Bag Liner

Boost the warmth and performance of your sleep system with the Reactor Fleeceweight sleeping bag liner. Built with Thermolite® hollow-core fibres and grid fleece, it traps and reflects body heat to add up to 8°C / 14°F of extra warmth with minimal weight or bulk.

The stretch fleece construction and integrated arm openings provide freedom of movement, while snap attachments pair seamlessly with Sea to Summit sleeping bags for easy entry and exit. Quick-drying, easy to clean and treated with HeiQ Fresh odour control, it stays fresher for longer on extended trips.

Using a sleeping bag liner helps reduce the need for frequent washing, preserving loft and extending the lifespan of your sleeping bag — making it a smart upgrade for camping, hiking and cold-weather adventures.

Best Use

Cold-weather backpacking, Ski touring, (Stand-alone) summer use
Material(s)

100% Post-Consumer Recycled Polyester; Stuff Sack: 100% Polyester