Cocoon Vapor Barrier MummyLiner

The Cocoon Vapor Barrier MummyLiner is a simple, lightweight sheet designed to slide inside your mummy-style sleeping bag. It serves to manage moisture and help keep the insulation of your bag drier, making it a useful addition for cool, damp nights in the backcountry.

Constructed from 100% nylon, this liner packs down small and adds minimal weight to your kit. By creating a vapour-blocking layer, it can help maintain the loft and warmth of your sleeping bag around its 5°C comfort rating, giving you a bit of extra security against chilly, humid conditions.

A vapour barrier liner works by preventing water vapour from passing through to your bag’s insulation. When moisture from sweat stays against the liner instead of soaking into the insulation, the fill stays dry and retains heat more effectively. This straightforward approach can boost your bag’s performance in cold, damp environments.