Performance Machine Bolt-On 4-Piston Caliper Kit For Harley Features: Front Left Caliper is 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 11.5 and 11.8 disc applications Include brake pads, bleeder screw and 3/8-24 banjo bolt Requires 11/16 master cylinder 501-058, 501-057 or 501-059 for optimal performance