The Blue 300 Firm model combines the feel of an extra-firm mattress with the benefits of our latest breakthroughs in memory foam technology. It combines our TempActiv Gel Memory Foam with a layer of EverCool Fuze Memory Foam for enhanced cooling comfort that also supports every curve of your body. It also features a layer of Deep Reaction Memory Foam for a substantial, deep-down feel not often found in traditional memory foam.