The Wenzel Sunward 40°F Sleeping Bag offers lightweight comfort with 3-season versatility. Both the shell and liner are made of light yet durable 190T Polyester, delivering a long-lasting, comfortable, and easy-to-carry bag. The Insul-Therm insulation provides the necessary warmth and quilt-through construction provide the ideal level of warmth, keeping you cozy without over-heating. Plus, the large 2-way zipper lets you open the bottom in case some extra ventilation is needed. Wenzel Sunward 40°F Sleeping Bag Rectangular 40°F sleeping bag, great for summer camping adventures Durable Polyester shell provides a lightweight and long-lasting exterior Filled with 4 lbs. of Insul-Therm insulation for extra warmth Quilt-through construction with 190T polyester liner keeps you cozy without over-heating Large 2-way main zipper for optional venting, or un-zips fully to serve as blanket Hook-and-loop with Wenzel logo conveniently secures zipper in-place Includes rugged stuff sack with tyvek for easy packing and portability.