12 Inch Ashley Hybrid King Adjustable Base and Mattress2 Piece King foundation and Mattress The Hybrid 1200 king mattress and king mattress foundation set is simply a better way to get a great nights sleep. The mattress gives the contouring support of a traditional coil mattress and the firmness of gel memory foam, providing restorative support for your lower back. The riser is an all in one support system that takes the place of an ordinary bed frame and box spring. And setup is as easy as 1 2 3. Step