Low note horn nut. A solid metal or plastic block with a threaded hole in the center which is used to tighten or adjust the Exhaust System Hanger. A solid metal or plastic block with a threaded hole in the center which is used to tighten or adjust the Floor Pan Splash Shield. Bumper Impact Bar Nut. Exhaust Flange Nut. Horn Nut. Vapor Canister Nut. Window Regulator Nut.