Protect-a-bed AllerZip pillow covers protect pillows against bed bugs, allergens, dust mites, dirt and liquids. Unprotected pillows create the perfect breeding ground for bacteria and dust mites, or provide harborage for bed bugs. Now you can protect these sensitive areas with Protect-a-Bed pillow covers. Each cover is machine washable and made of soft, terry cotton so the pillows remain cool and comfortable to sleep on.