Designed to significantly improve nighttime comfort, the Reactor Lightweight sleeping bag liner uses a combination of Thermolite Pro hollow-core fibers andfar infrared (FIR) technology. This combination retains and reflects body heat to increase the internal temperature by up to +4°C, without adding weight or bulk. Lightweight and compact, it quickly becomes an essential companion when the nights get cooler, whether you're trekking at high altitude, camping in the wild, or backpacking.

A stretchy fabric that lets your body move naturally

Its elastic knit fabric offers great freedom of movement and easily adapts to all sleeping positions. Thanks to its ingenious design, you can easily get in and out of the sleeping bag liner, and it connects perfectly to SEA TO SUMMIT sleeping bags for a more intuitive setup. This natural mobility allows you to enjoy a deeper and more restful sleep, even over several nights in a row.

Sustainable hygiene and enhanced protection for your sleeping bag

The Reactor Lightweight features HeiQ Fresh odor control treatment, which helps the fabric stay fresher, even with extended use. It washes easily, dries quickly, and forms a protective layer between you and your sleeping bag, reducing friction and the frequency of washing. By preserving the loft of the bag, it helps to extend its life while optimizing the thermal performance of your sleeping system.

Improve your nighttime comfort without adding bulk: choose the Reactor Lightweight and enjoy immediate warmth for a peaceful night's sleep in the coolest environments.