The Fleece Cover is a rectangle fleece liner that can be used year round - as an accessory or as a standalone bag. It is a great "accessory", even if you already have several bags. It can help add extra warmth on those extra cold nights. As a standalone bag, it can be used in warmer temperatures when you only need a very lightweight bag. It comes with a fleece carry case that features a handle for easy transport and can be stuffed with extra clothing to make a comfortable pillow. With a bag that works, whether it is warm or cold, you can't go wrong with this choice… a value that lasts all year long!