The Sierra Designs Frontcountry Bed is a zipperless sleeping bag with a unique design. Enter the bag via a large opening in the top the oversized, integrated comforter seals the opening so you sleep comfortably and naturally on your back, side or stomach. The oval opening is designed to intuitively adjust in width to prevent cold drafts, yet it wont restrict your natural sleeping position. Versatile Integrated Comforter: Wraps naturally to your preferred sleeping position and allows you to easily adjust to varying temperatures. Self Sealing Foot Vent: Zipperless vent self seals and can be operated from the inside using only your feet to easily adjust to varying temperatures. Insulated HandArm Pockets: Provides insulation under your arms when comforter is used outside the bag. Zipperless Design: No additional hardware, cords or Velcro to get in the way. Catenary Shaped Opening: Opening is smaller than the bag width so when you push out, the walls push in, to seal out drafts. Pad and Air Mattress Compatible: Fits standard air mattress. Adjustable Sleeping Pad Sleeve: Secures your sleeping pad to create the experience of a fully integrated bed. Room for Standard Pillow: Hood is sized longer and taller to accommodate a standard pillow and your head. Fully insulated bottom.