Choose from the available size options. Gel memory foam and innerspring hybrid mattress. 12.75 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. A combination of cooling memory foam and innersprings ensure you'll sleep deeply on the Beautyrest Platinum Jaycrest 12.75 in. Plush Mattress. This plush mattress features an InfiCool HD surface that moves heat away from your body as you sleep. Its memory foam layers include ActivPur for antimicrobial benefits and gel bead-infused memory foam, plus pocketed coil technology for conforming support that won't wake your partner every time you move. This mattress is offered in your choice of available size. Complete it by adding the optional box spring foundation, which is offered in a choice of available sizes and heights. Size: Twin.