Choose from the available size options. Cool gel memory foam and motion reflex mattress. 13 in. thick hybrid mattress. ActivPur and AirCool gel memory foam layers. Motion reflex layer maximizes cooling air flow. Optional box spring in choice of available sizes, heights. 10-year manufacturer's warranty. For a deep, restful sleep, the Beautyrest Platinum Hybrid Atlas Cove 13 in. Firm Mattress offers multiple layers of cooling memory foam plus motion reflex. The layers include an InfiniCool HD surface with cooling materials, ActivPur memory foam infused with platinum for cooling, antimicrobial benefits, AirCool gel memory foam, and motion reflex. This mattress is offered in your choice of available size options. Make it complete by adding the optional box spring foundation, which is offered in a choice of available sizes and heights. Size: King.