Mueller-Kueps 433 501 Grinding Disc, (Pack of 3) (for Type 1 Holder Replacement) Special grinder for cleaning the wheel and hub contact surfaces Burned in corrosion residues are completely removed in a quick and easy process Actual process time per hub is about 3 - 25 seconds depending on thickness of corrosion. Work with Mueller-Kueps Wheel Hub Grinder Type 1 (433 502/M)