The Thermarest NeoAir was the sleeping pad that started it all. By producing a matrix style insulation system Thermarest was able to cut out heavy foams or insulative materials. The NeoAir offered loft without weight, and the XLite takes the NeoAir to the next level. Now warmer, lighter and mummy cut the XLite keeps your body heat from escaping into the cold ground without weighing you down on the trail. Utilizing the reflective heat technology from the original Neo Air Thermarest has improved the design, producing a product that will help you sleep better in the mountains.