The Sea to Summit Comfort Blend Rectangular Sleeping Bag Liner functions as the core of your sleep system, keeping your sleeping bag clean and improving your sleep climate. The combination of a polyester stretch-knit fabric and TENCEL Lyocell fibers provides an exceptionally soft, comfortable, and moisture-wicking layer next to your skin, assuring a great night's sleep. HeiQ Fresh odor control technology helps keep your liner fresh even with extended use. 70% polyester/30% TENCEL Lyocell. Rectangular shape with standard-size pillow sleeve. Mfrs. limited lifetime guarantee. 70% polyester/30% TENCEL Lyocell Use inside your sleeping bag for extra comfort Polyester stretch-knit fabric with TENCEL Lyocell fibers Soft, comfortable, and breathable HeiQ Fresh odor control technology Fits any rectangular sleeping bag