Big Agnes Sleeping Bag Liner Features Designed to regulate your temperature in a variety of conditions and uses Keeps your sleeping bag clean and protected while adding 5 - 10˚ of warmthStands alone as a packable layer for travel and warm-weather overnights under the stars Wool's natural thermal properties are ideal for adding heat in the winter and cooling you off in the summer Features a generous 42" side opening; snap closed for increased insulation or open for maximum ventilationEasily reversible to fit right or left zip sleeping bagsMinimalist cinch-hood closure Durable seam construction is smooth and comfortable against your skinHooks located at the head and foot allow for easy attachment to sleeping bag liner loops Stuff sack included Construction + Materials 87% New Zealand Merino wool, 13% nylon for added durabilityNylon rip-stop and polyester mesh stuff sack Durable seam construction is smooth and comfortable against your skinLength: 82" / 208cm