Choose from the available size options. Cool gel memory foam and innerspring mattress. 13.75 in. thick hybrid mattress. ActivPur, gel bead-infused, and GelTouch memory foam layers. Individual pocketed coils for motion separation. Optional box spring in choice of available sizes, heights. 10-year manufacturer's warranty. For customized, firm comfort while you sleep, choose the Beautyrest Platinum Spring Grove 13.75 in. Luxury Firm Mattress. This firm hybrid mattress combines the cooling pressure point relief of memory foam layers with Beautyrest pocketed coil technology for a balance of conforming support and motion separation. This mattress is offered in your choice of available size. Make it complete by adding the optional box spring foundation. It's offered in a choice of available sizes and heights. Size: King.