Best Choice for Allergies! Sleep Safe ZipCover"s EVOLUTION Award Winning EVOLON® Fabric * Provides the perfect physical layer to protect against Bed Bugs, Dust Mites & Allergens. * Baby-Safe! Breathable cotton-like comfort resulting from unique microfilament technology. * Bleach-Safe! Maintains performance & efficacy after repeated washings up to 200° Fahrenheit. * Sleep Safe EVOLUTION Encasements are Free of PVCs or Chemical Post Treatments for Better Health.