The top of the mattress has the ability to be zipped on/off and features a soft fiberfill material sewn into the mattress top. Sleep Number says the zones are intended to relieve pressure and contour to the head and neck, back and hips. The C4 model comes with a 1.5 inch “Comfort layer” of polyurethane foam that features 3 zones of comfort. The hoses to pump air into the chamber are 4ft in length. Sleep Number calls this “DualAir™ adjustability” and it allows people to adjust firmness and support on each side of the bed to the Sleep Number setting. Inside the mattress, there will be 1 or 2 air chambers, depending on the size of the mattress.

The C4 mattress is 10 inches thick (measured from the base to the top of the mattress)Īnd made with a soft and breathable polyester/polypropelene knit blend.