MD 106 Foam Encased 10.5" Pillow Top Mattress and Box and Box set is available in twin, full, queen, or king size. The pillow top mattress comes with inner spring and 360 degree foam encased support, which provides a firm, yet soft surface for a great night's sleep. When you purchase the king size mattress and box set, you will be provided with two separate, identical mattress box foundations that will fit underneath a king size mattress.