Made in the USA, the Ultra mattress protector utilizes performance stretch polyester comfort materials, similar to sports apparel. Key to the comfort it provides is the very thin layer of polyurethane fused to the back of the fabric which allows it to be waterproof and breathable. This cover also helps you maintain an ideal sleep temperature. "Snapfit" technology allows it to fit any mattress height and works perfectly on adjustable bases without the corners popping off.