The hybrid shape of the Coleman Big Basin 15 Big & Tall Sleeping Bag gives you all the added warmth of a mummy and the extra space of a rectangular bag. On warmer nights, simply keep the adjustable hood loose and open up the two-way zipper to get custom ventilation. When things cool off, lightweight Coletherm hollow polyester insulation helps to retain heat, and the Thermolock draft tube helps to block warmth from escaping through the zipper. The fleece-lined footbox and special quilting construction surround your feet.