SnoJax I Snow Guards 20pcs Screws and Sealant Kit for Metal and Steel Roof Panels Includes 40 galvanized #14, self-drilling screws, 2 inches long, with an attached neoprene washer. Fits most exposed fasterner metal panels and can straddle ribs! Starter points are provided for mechanically fastening. ATI lab tests show 1,800lbs strength with mechanical attachment. Free layout at www.SpacingTool.com