This Allergin Barrier dust mite protective pillow cover is a great. It is a specialized zippered pillow protector cover. This woven high thread count nylon cover is for any standard Size 20"x30" pillow (pillow not included). It had a specially designed high quality zippered closure to enhance protection. The allergin barrier fabric is a high thread count, finely woven fabric that is constructed of a network of fine pores through which moisture vapor and air can pass. As a result of the pores being less then as micron in diameter, allergins such as dust and dust mites can not get through. This is a high quality pillow and at this price, it is a real bargain!