These nuts have a serrated flange that grips into the surface and doesn't let go! Flange Nuts are identified by the built-in washer that acts to distribute the clamping load over a greater area. They are designed to provide the same holding power as if you were to use a washer. The zinc plating makes them highly resistant to corrosion, with a shiny silver finish. These nuts are superior to original or OEM product, and are made to withstand high strength and extreme conditions. High quality commercial grade bolts for less