FT SILVER is a contractor grade steep slope roofing underlayment, it is a cost effective, and reliable 30 felt replacement product. It is easy to install, and has 5X more coverage per roll as compared to #30 felt. FT SILVER offers a wrinkle free surface that lays flat, and stays put with its underside non-slip coating. It is designed for use under; primed cedar, asphalt, synthetic shingles, and residential metal roofing.