Designed primarily for comfort, the Silk Blend Liner adds warmth to your sleeping bag via the 72% Thermolite Pro yarns with infra red technology, Thermolite EcoMade fibres and 28% silk. The combination creates a soft, luxurious sleep environment. Comfort Stretch Panels along the seams boost sleeping comfort. Shoulder openings and a drawcord footbox add temperature regulation (and match the Free-Flow zippers of Sea to Summit sleeping bags). The Silk Blend Sleeping Bag Liner features: A liner is the climate core of your sleep system - the Silk Blend liner adds warmth and a touch of luxury to your sleeping bag Hollow-core Thermolite Pro fibres create a warmth-trapping layer around you, enhanced by infra red absorbing ceramic pigments HeiQ odour control technology helps keep the liner fresh even after extended use Drawcord footbox can be opened or closed for optimal comfort, and harmonizes perfectly with the Free-Flow footbox zipper of Sea to Summit sleeping bags