Provides a protective barrier around your mattress that locks out and eliminates bed bugs, dust mites, pet dander, pollen, and mold spore allergies once and for all. Made of a light and breathable 100% Polypropylene with a Polyurethane membrane for the ultimate in comfort with a maximum pore size of 1 micron. Provides protection from allergen molecules of less than 1.0 microns. Prevents breeding bacteria and is waterproof. One year guarantee*. Based on allergist expertise, we created the Zip & Block range of zippered mattress, box spring, pillow and duvet encasing. As medically recommended, they are manufactured with an outer zipper flap, an interior zipper flap and reinforced inner seams for the most effective barrier to related allergens. Extra long rustproof zipper for easy insertion. Zipper has both an outer and an inner flap closure for extra protection. Binding on inside seams for extra strength and protection. Fully-encased, provides complete coverage!