Change the way you sleep with this Hamilton Firm mattress from Spring Air. A 450 (Queen) Hinge-Flex Plus Knotted Offset Coil system is sensitive to the contours of your body while also extending the life of the mattress. A layer of Polyurethane Foam and a layer of High Resiliency Foam work together to provide unmatched firmness, support, and durability without leaving body impressions. Additionally, this mattress is kept comfortable at an ideal temperature thanks to the 4-way stretch knit fabric with Joma® wool and a high density convoluted foam. This firm mattress is perfect for stomach sleepers.