Comfort top mattress protector with bed bug blocker provides powerful protection against bed bugs, dust mites, and other allergen irritants. Begin with a soft knit fabric and line it with a special permanent coating. This coating, along with the double sewn seams, provides a complete barrier. The encasement closure is extra secure and features a triple-seal closure system which has an inner flap, a hook & loop hidden seal and a nylon zipper to block bed bugs and dust mites, as well as allergy irritants.