Olee Sleep 6 in 3 Layer Ventilation Memory Foam Mattress (Twin) 06FM01T 4 inch High Density Foam Convoluted Layer helps make flow to ventilate air 1 inch HD foam support your back Line. 1 inch Memory foam mould your body shape. Pressure relief material that adapt to your body shape, weight and temperature HD ILD 20 Density 32 D Pound will give you firm Mattress feel