Therm-a-Rest Z-Lite Sol the lightest most compact closed cell mattress on the marrket. Therm-a-Rest's unique folding eggbox design which ensures that it packs down to a fraction of the volume of a traditional roll mat, it also dramatically increases the warmth and comfort of the mat compared to other ultralight foam mats. A favourite amongst the ultralite elite the Therm-a-Rest Z-Lite Sol features a compact accordion-style shape and heat-trapping dimples. The Therm-a-Rest Z-Lite SOL has the reflective ThermaCapture coating that helps capture radiant heat, increasing overall warmth by nearly 20%. The proprietary foams are softer on top for extra comfort and denser on the bottom for extra durability.