Harley Davidson Brake Caliper Performance Machine 11.5″ 4 Piston Caliper is a 4 piston differential bore with dual pad design Differential bore pistons apply different forces at the leading and trailing edge of the pad to ensure long life Designed for 11-1/2″; disc applications Requires 11/16″; master cylinder 501-058, or 501-057 or 501-059 for optimal performance Features differential bore pistons that apply a different force at both the leading edge and the trailing edge of the pads to ensure superior breaking Dual-disc applications require the separate purchase of a left and right front caliper Include brake pads, bleeder screw and 3/8in.-24 banjo bolt For 11.5/11.8in. (300MM) rotors (137 x 4B calipers) Calipers listed for 2000-2003 XL models will fit 2004-2012 XL models if used with a 9/16in. bore master cylinder Made in the USA