MEDIUM FIRM HYBRID MATTRESS: Combined the strong support of high manganese steel springs with the plush comfort of memory foam, Avenco 12'' cal king hybrid mattress provides a evenly support with medium firmness and avoid morning soreness caused by the over-sagging or hard mattresses. PRESSURE RELIEF: Composed of totally 4 layers of gel-infused memory foam and high density foam, the comfort layer of this california king size bed mattress provide enough cushion to cradle your pressure points, which will be like sleeping in a hug without excessive sinking MOTION ISOLATION & EDGE SUPPORT: Innerspring base made of hundreds of individual pocket springs is divided into 7 zones to give a right support for every inch of your body. Each coil reacts movement separately, which help to reduce motion transfer and noise made by your partner. Reinforced foam maximize edge support and protection to avoid falling when sitting on the edge of our california king spring mattress.