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The Cocoon Flannel KidSack liner adds a layer of warmth to a child's sleeping bag-or use alone as a summer sleeping bag. Made from soft, brushed cotton flannel. Keeps a kid's sleeping bag clean and extends the life of sleeping bag. Used as a liner for a rectangular sleeping bag, it adds 12.1degF to the temperature rating. Features a drawstring hood and a pillow pocket. Cocoon Flannel KidSack liner packs down small into the included drawcord storage bag.