Designed to perform in some of the most adverse sleeping conditions in the world, the Mammut Altitude EXP 8 Degree Winter Down Sleeping Bag will keep you comfortable whether you're sleeping on a portaledge, camped out in the resort parking lot, or waiting for the storm to clear at camp before launching a summit bid. Where the Altitude EXP really stands apart is with its ShelterTX waterproof, breathable shell, which prevents moisture from contacting the down fill, making this bag well equipped to handle adverse weather conditions. The bag itself incorporates Mammut's Trinity construction at the head and feet, which provides better coverage while increasing insulating properties. Box construction through the body provides a more comfortable fit than standard mummy shaped bags while also adding to the bag's insulating performance. Nine chambers ensure the foot area remains well insulated throughout the night, and the 12 baffle hood protects against heat loss. The inside of the the bag features a large draft collar along with one internal pocket to store anything you might need throughout the night.