Our mounting hardware options are all made from black oxy-coated steel. Our black oxy-coated steel allows us to insure extra duty strength as well as offer rust resistant charecteristics. When used to mount a Solid Back, the bracket offers depth and angle adjustability. When used to mount a Solid Seat, the bracket provides height and angle adjustability. The 7 hole "L" bracket w/ the 7 hole "J" hook (for 7/8" tubing) provides significant adjustability for the Insert