2 and 4 piston calipers machined from heat-treated aircraft quality, billet aluminum 5/8 in bore master cylinder required for single disc.
3/4 in bore for dual disc applications 2 piston calipers utilize two 1-5/8 in pistons.
4 piston calipers use four 1-1/4 in pistons Kits include brake pads, hardware and brackets GMA Caliper Model - A Made in USA This product can be used with Model Part# Harley-Davidson Sportster Late 87-99 BA2PRCKHD-1 Harley-Davidson Big Twin (10 in Rotor) 73-80 BA2PRCKHD-2 Harley-Davidson Big Twin (11.
5 in Rotor) 81-84 BA2PRCKHD-3 Harley-Davidson All 36-Up BA2PRCKHD-4 Harley-Davidson All Aftermarket Rigid 3/4 in Axle 10 in Rotor BA2PRCKHD-4 Harley-Davidson Softail 87-99 BA2PRCKHD-5 Harley-Davidson FLT 86-99 BA2PRCKHD-6