The Cool Gel Gen 2a has a Base Foam is 6″ of HR (High Resilient) Durable Foam. 2″ Transition layer consists of 1.820 Polyurethane Foam 2″ Top layer consists of Gel Infused Visco also known as (Memory Foam) The top fabric covering made of a channel phase change, cooling material –The benefits of Gel Infused Visco (Memory Foam) *Provides a supportive, yet soft surface promoting enhanced Circulation, proper pressure relief, and spinal positioning. *Gel enhancements assist in maintaining temperature for added comfort –The Benefits of Phase Change Material *Assists greatly in releasing unwanted heat *Assists in maintaining a more comfortable sleeping temperature *Durable long-lasting fabric