Zippered Impermeable Pillow 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 mold proof & dust mite impermeable pillow 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 pillow encasings can not be measured in terms of mean pore size*. The fabric stretches as you move for supreme comfort. Machine washable, BedCare Classic encasings carry a Lifetime Warranty, have premium, rust-proof zippers, and reinforced seams. Money back guarantee! Product Notes:* Using bleach or drying on high temperatures will diminish the water-resistant properties of this fabric.* Many doctors recommend putting tape on the zipper to be sure no allergens escape. Made in the USA. Queen Size measures 21" Wide x 31" Long.