Top opening bivy sack with 32 inch zippers on both sides. The zippers have 3 sliders each to allow for a variety of ventialtion options or to stick arms out. The opening is backed by no-see-um netting. Both the opening flap and the netting are attached to the brim with velcro. A wire stiffener is sewn into the brim. The top material is waterproof/breathable (Tegraltex) and the floor is coated nylon. Available in two sizes: regualr and long. The specifications listed are for the regualr.