Envelope style sleeping bag that can be used alone comfortably in 3 seasons. This sleeping bag has fiber lock construction so that the material does not shift when you move inside the bag to prevent bulging and discomfort while you sleep. In addition it has a no snag zipper that allows for ease getting into and out of the sleeping bag. The zipper can open and close from the top or the bottom so you can let just your feet out if you like. The Velcro on the top keeps the zipper closed while you sleep. The drawstring on the top portion allows for you to close the sleeping bag around your head for additional warmth or around a pillow to hold it in place.