Zippered Impermeable Mattress Covers are the #1 Way To Dramatically Reduce Dust Mite Allergen Exposure! Ultra-Soft Knit Fabric With A Protective Lining Completely Seals Off Mold and Dust Mite Allergen Plus Bed Bugs. BedCare Classic dust mite and mold impermeable mattress covers are made of a lightweight polyester knit fabric joined to an ultra-thin, allergen-proof Comfortech polyurethane membrane making them water resistant as well. Because of this barrier membrane, these mattress encasings can not be measured in terms of mean pore size. The fabric stretches as you move for supreme comfort. BedCare Classic encasings are machine washable, carry a Lifetime Warranty, have premium, rust-proof zippers, and reinforced seams. NOTE: Using bleach or drying at high temperatures will diminish the water-resistant properties of this fabric. For complete protection doctors also recommend covering your box spring with a Sleep Fresh Vinyl Box Spring Encasing. 12inch Queen Size measures 60inch Wide x 80inch Long x 12inch Deep.