Choose from the available size options. Memory foam and innerspring hybrid mattress. 13.5 in. thick hybrid mattress. ActivPur and gel bead-infused memory foam layers. Individual pocketed coils. Cooling support contours to your body. Optional box spring in choice of available sizes, heights. 10-year manufacturer's warranty. The Beautyrest Platinum Spring Grove 13.5 in. Extra Firm Mattress offers the cooling, pressure point relief of memory foam plus innersprings for support. This is an extra firm mattress with an InfiCool HD surface that moves heat away from your body as you sleep. Memory foam layers include ActivPur for antimicrobial benefits and gel bead-infused memory foam with the combination of pocketed coil technology that offers maximum support and won't wake your partner when you move. This mattress comes in your choice of available size. Make it complete by adding its optional box spring foundation, which is offered in a choice of available sizes and heights. Size: California King.