Thermarest ridgerest solar camping mat large the ridgerest solar is our warmest thickest and most comfortable foam mattress it boasts a heat reflecting thermacapture tm surface adding to the effectiveness of heat trapping valleys and soft supportive ridges to deliver the warmth you need for camping in any season for maximum warmth use reflective side up all season warmth patent pending aluminized surface reflects radiant heat amplifying the effectiveness of heat trapping valleys