polyolefin elastomer, also called air net or air coil, it is air permeable, breathable, anti-mite, anti-mildew, anti-bacteria, anti-stuffiness, hypoallergenic, anti-suffocation, washable, quick dry, high elastic and durable, non-toxic, eco-friendly. it is highly effective for anti-decubitus and easy to be clean up. so it is suitable for medical care, family daily use and completely safe for baby.