Use the internal spline lock ring for rear hubs and most front QR and 12mm hubs. Use the external spline lock ring for 15 and 20mm front hubs.
Centerlock hub rotor shim (pack of 4)
Disc Brake Rotors
6 Bolt Disc Rotor Shim
Kool Stop Dura 2 Brake Pads (for alloy rims)