The mattress is 26cm Deep features 13.5 Gauge Bonnell Open Coil Spring Unit with Polyester, Classic filling, and Deep layer of memory foam. It provides exceptional respond to heat and weight. Absorb the pressure and provides the perfect support to the whole body. The top deep later of memory foam is used to enhance the comfort. When you lie down your pressure points produce friction causing heat, softening the memory foam giving you the correct support whatever your weight or shape, also relieving all pressure down your body. When you are out of your bed the memory foam will recover to its original shape