Not sure which rebuild kit you need ? Use the info. below to match your caliper with the rebuild kit for your application.
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
600 series use 6 seals, one per piston
6000 series use 12 seals, two per piston