Not sure which rebuild kit you need ? Use the info. below to match your caliper with the rebuild kit for your application.
4 piston
100 series calipers, both pistons are the same size.(Also used to rebuild HHI Driveside Inboard Brake Caliper.)
500 series calipers, one piston is small the other is large
6 piston
600 series use 6 seals, one per piston
6000 series use 12 seals, two per piston