Chinook Everest Extreme -40° F Mummy Shaped Sleeping BagThe Everest Extreme is among the warmest Chinook Sleeping Bags on the market. It features Invista Thermolite Extreme insulation for temperatures as low as -40 degrees Fahrenheit. The mummy shape allows maximum heat and space efficiency. Sleeping Bag Details:Waterproof and anti-slip HiTex bottom fabricErgonomic head gasket and foot boxSnughood design over facial area for best fit, extra comfort, and bulk reduction.Oversize draft tubes and neck collar provides added protection4 layer shingle designPongee Pro lining#8 YKK 2 way Zipper - Reversible Puller - Auto lock stuff sack cap compression bagDraw cord fully tightenCan be zipped with other compatible bagsMummy shapeTemperature Rating: -40 degrees F5.7 lbs - 90" x 34" x 22"Made by Chinook - Outdoors and CampingThe name is not a misnomer. When they called this sleeping bag the "Everest" they definitely intended on the implications! -40 degrees?! That's cold!!! But not with the Chinook Everest Extreme!