Made of 1/4" thick mild steel with mounting holes for a Wagner or Kesley style rear master cylinder on your Harley 4-speed transmission. The master cylinder mounting holes are 5/16". You will need a longer clevis with Kesley style master cylinder (we have it for $20 you can add it from the option box), or you can extend your brake plunger rod. You will also need longer kicker cover studs or swap them for bolts.