This Medium Firm mattress features a durable high density 6” foam core with 2” of pressure-relieving Serene® foam. Better than memory foam, products from the Serene® Collection are made with Serene® foam – the most advanced foam on the market. Serene® foam is enhanced with Supportive Air Technology™, increasing the level of support without compromising comfort. The simplicity of this mattress is its strong suit: no convoluted foams to break down into support loss. Its high density core is a better grade than you’ll find in many of the top online brands.