PureCare's Cooling 5-Sided Mattress Protector combines our specially designed OmniGuard® Advance fabric with rapid chill cooling fibers€š a micarex-based responsive textile with unique cooling properties. FRíO's rapid chill cooling fibers disperse body heat throughout the surface of the protector at a rate five times faster than that of regular polyester, focusing solely on heat reduction along the sleep surface through a combination of nano-technology, nylon, and mica minerals. The unique tunneling effect of the mineral-based fiber keeps heat from accumulating in the material surrounding the body, providing a refreshingly cooler sleep surface. FRíO's rapid chill cooling fibers are a crushed mineral infused textile, meaning the cooling effects of this material are literally built into the fabric and will not wash out, lasting the lifetime of the protector.