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 & 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. NOW with BugShield Technology to protect you and your bedding from bed bugs. Made in the USA. Twin Size measures 39" Wide x 75" Long x 9" Deep.