Made with patented technical fibers, this is the only reversible mattress protector with a cooling or warming side that helps improve the quality of your sleep. On the cooling side, a proprietary fiber infused with micarex minerals disperses body heat five times faster than ordinary polyester, providing a refreshingly cool sleep surface. When the protector is reversed, insulating fibers accumulate your body’s natural heat to help maintain a comfortably warm temperature all night long. Also provides a barrier against allergens, moisture, dust mites, mold, and mildew. The five-sided protector fits mattresses up to 17 1/2" H, it is treated with antimicrobial silver chloride that inhibits bacteria, mold, mildew, and odors, and its cooling/heating performance won’t diminish with machine washing and drying. Official mattress protector of the National Sleep Foundation and recipient of a Women’s Choice award. 100% nylon Mica fiber with 100% viscose polyurethane membrane. Imported.