THERMAREST NEOAIR XTHERM CAMPING MAT (LARGE) Thermarest NeoAir XTherm Camping Mat The XTherm TM air mattress delivers, by far, the greatest warmth-to-weight ratio available in any air mattress, allowing you to go lighter than ever in winter conditions. Patent-pending ThermaCapture TM Radiant Heat Technology gives the XTherm TM air mattress true four-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 about the same space as your water bottle, and provides serious comfort in extremely cold conditions. Pump sack and repair kit included. Unmatched Warm-to-Weight: Patent-pending, reflective ThermaCapture TM technology traps radiant heat while Triangular Core Matrix TM construction minimizes convective heat loss-all without the bulk, weight or durability issues of down and synthetic fills. Comfortable: 2.5" (6 cm)-thickness and baffled internal structure provide unrivaled stability and support. Highly Packable: Free of bulky, conventional insulating materials, the XTherm TM mattress packs to the size of a one-liter water bottle. Ultralight: Advanced materials and a tapered design reduce weight without compromising warmth. Note: The Regular is 6 inches longer then medium.