The BedCare Classic dust mite and mold-impermeable mattress cover is made of a lightweight polyester knit fabric bonded to an ultra-thin, allergen-proof ComforTech polyurethane membrane that makes this a waterproof cover as well. Because of its barrier membrane, this protective cover cannot be measured in terms of mean pore size though It is nearly zero! The soft, satin-like fabric stretches as you move for supreme comfort, making this an excellent allergen cover for your bed. Zipping your mattress into this encasement provides total protection on all sides with no gaps or openings. Bed Bug Proof: As an added bonus, this bedding set is also bedbug proof. Made with our patented BugShield system with an auto lock zipper that will not backtrack when closed. The BugShield Bug Blocker is an added barrier that closes the last inch or so of the zipper from below to create a fabric shield under the zipper closure to doubly ensure that bed bugs will not be able to get in or out of the encasing. Zip closure Waterproof Dust mite proof Bedbug proof Lifetime warranty Imported Product Specifications 52 in L x 27 in W x 6 in D Material & Care Polyester Machine washable