If you read our Layla review you will find out that each outer layer consists of a high density memory foam infused with copper (one of 3" and the other of 1" thickness), the air-flow transition layer is convoluted polyurethane foam and the support layer consists of high density polyurethane foam. Note: Polyurethane foam is commonly referred to as 'poly foam'. The support layer is next to the 1" high density memory foam layer. The transition layer lies between the support and 3" memory foam layers.