Pro-Tek RC-100K Black Front or Rear Brake Fluid Master Cylinder Reservoir Cap Front or Rear Brake Fluid Master Cylinder Reservoir Cap in black anodized finish This round threaded front or rear brake cap (Pro-tek Part No. RC-100) is 2.25" x .50" and has the word Pro-tek engraved on it twice 100% CNC made from 6061 T6 billet aluminum Replaces only the stock plastic caps.