Still the top choice for adventurers seeking lightweight and durability, the Therm A Rest Z Lite Sol Mattress is warm and comfortable. The new thermal reflective barrier increases overall warmth by 20%. The Sol is the right choice for people seeking ultralight sleep anywhere warmth, durability and comfort. Weighing less than a pound, this mattress goes anywhere easily. Accordion style design packs lots of comfort into as small a space as possible. Closed cell foam is incredibly durable, providing an exceptional value and many years of worry free performance. All new proprietary foams are softer on top for extra comfort and denser on the bottom for extra durability.