The XTherm mattress is the warmest mattress in the NeoAir collection, allowing you to go lighter than ever in winter conditions. Patent-pending Reflective Barriers give the XThermTM mattress true 4-season warmth without the weight or bulk usually found in a winter-worthy mattress. The result is a mattress that weighs less than a pound, takes up less pack space than your water bottle, and provides serious comfort in extremely cold conditions. Pump sack and repair kit included. Features: Extremely Warm: Four layers of reflective material recycle body heat and create air pockets that reduce convective heat loss. Comfortable: 2.5-inch thickness and patent-pending Triangular Core MatrixTM construction provides unrivaled stability and comfort. Highly Packable: Low-bulk materials make the XThermTM mattress compact and as packable as a water bottle. Lightweight: Advanced materials and a tapered design reduce weight without compromising warmth.