Thermarest Evo Lite Self Inflating Mattress Description: The Evo Lite re-charts the future of self inflation. It's only logical, that as inventors of the self-inflating mattress, Therm-a-Rest would take its unmatched experience & know-how to move self-inflating technology into the future. Blending the convenience of self-inflation with the comfort of air, the patent-pending Evo Lite mattress is poised to become the greatest thing in outdoor comfort.