The 400 TC cotton cotton surface and box-stitched quilting add functionality and appeal to the Quilt Tite mattress protector. A soft layer of down alternative filling helps to create an air layer for better circulation, breathability and comfort. The laboratory-certified H2Pro liquid-proof membrane adds a protective barrier against allergens, dust mites, and liquids. The Universal Fit design guarantees a secure fit for mattress depths 6"-22" and gives five sides of protection for your mattress top and sides.