To add warmth and a luxuriously soft touch to our sleeping bag experience, we turn to Sea To Summit's Silk Blend Sleeping Bag Liner. This liner's fabric blend of Thermolite Pro, Thermolite EcoMade, and silk fibers delivers us a soft, toasty sleeping experience in the great outdoors. We also appreciate the HeiQ odor control technology keeping things fresh even after extended use, and how the adjustable drawcord footbox can be opened or closed for optimal comfort.