The Protect-A-Bed premium mattress and pillow slip covers are made from a blend of cotton and space age polymer materials that combine the soft feel of terrycloth with the waterproofing qualities of polyurethane film. Using an electro-static process, these materials are permanently fused together. Protect-A-Bed fits over your mattress just like a standard fitted sheet, completely waterproofing your mattress from all liquid. In addition it also eliminats dust mites and bacterial growth on your mattress surface, and reducing the hazards of asthma, eczema, and rhinitis. They can be washed and dried with your bed linens, even sterilized at temperatures up to 250 degrees Fahrenheit. Ideal for cases of incontinence or high traffic, high activity areas where your mattress is at risk! Wash and dry hundreds of times. Put directly onto your mattress and place your fitted and flat sheets over the Protect-A-Bed.