Western Mountaineering Hotsac VBL Sleeping Bag Liner

This fire engine red vapor barrier liner is your most important companion for those technical winter trips. A VBL works by stopping heat loss from evaporative cooling. A VBL will also prevent your body vapor from degrading your insulation. This is most important during extended stays inside your bag. The Western Mountaineering Hot Sac VBL goes one step further by stopping radiant heat loss with its reflective metal coating. An elastic draw cord at the top of the Hot Sac cinches about your neck to prevent convective heat loss. This proprietary fabric is a new lightweight ripstop.