- Chrome plated - CNC machined billet aluminum - With a .100" center span to compensate for the thicker OEM rear FLT brake rotor - Designed for 11.5" rotors - ABS and Non-ABS compatible - 137x4B - 4-piston differential bore - Proudly machined with the PM icon logo - Designed to slow down fast; without flexing. Note: Bracket must be purchased separately; see catalog. Since the beginning Performance Machine has been in the forefront of brake caliper design; since 1982. Each caliper is precision CNC machined from billet aluminum for high-end performance calipers that combine lightweight; flex resistance; durability and a hard to beat styling. Available in various coatings to suit your taste.