This Gel Infused Memory Foam Mattress is constructed of all foam, with a thick layer of Ventilated Gel Infused Memory Foam with Phase Change Material as the top layer, providing a cooling, pressure relieving feel. This Ultra Plush mattress uses four layers of foam to transition from the softest to the firmest feel for an incredibly comfortable mattress. The foam core is encases with higher density foam providing a firmer edge. This mattress is good for a side or back sleeper.