This fitted-sheet style mattress protector is 100% polyester with a polyurethane backing that is waterproof and breathable. This repels liquids while allowing body heat to pass through without changing the feel of your mattress. Also 99.9% dust mite and allergen resistant. Machine wash in warm or cold water. Tumble dry on low or medium heat. Do not dry clean. No ironing needed. Bleaching will void warranty.