Flannel THE IMPOSSIBLE IS NOW WASHABLE: If you’ve ever had to hand wash your sleeping bag to protect the zippers and warranty this liner is the answer to your prayers; Liner ensures a clean, comfortable night’s sleep every time you use your sleeping bag MAKES ANY DOUBLE SLEEPING BAG WARMER: Soft, lightweight sleeping bag liner will add 10 degrees of warmth to your night PERFECT FIT FOR THE PERFECT SLEEPING BAG: Sleeping bag liner for your favorite TETON Sports Double Sleeping Bags; Mammoth Sleeping Bag Liner for the Mammoth and Fahrenheit Mammoth Sleeping Bags; Split sides for easy exit and entry EXTRA USES: Extra soft, brushed poly-flannel liner can also be used as a guest sheet or take it when you're the company; Liners make cozy travel blankets, especially in airplane seats where feet are always cold or on drafty benches TETON SPORTS PROMISE: Reach out to our AMAZING product support team if you have any questions or concerns; YOU CAN COUNT ON US to get you taken care of and back OUTDOORS with TETON Sports