With a terry top and 100% waterproof backing, the Sleep Tite PR1ME Mattress Protector is an essential addition to your bed. The quiet, 100% polyurethane backing blocks fluids, dust mites, and allergens, while the 80% cotton, 20% polyester terry top is absorbent and quiet, and it won't change the feel of your mattress. Air passes easily through the microscopic pores in the waterproof membrane for a breathable surface, and the mattress cover is great for asthma, eczema, and allergy sufferers because it's free of vinyl, PVC, and phthalates. The fitted-sheet style accommodates mattress depths up to 22 inches.