Diff maintenance tool, it helps you rebuild the ball diffrential on your touring car. These tools have two functions, the first is a diff ring holder with a small magnet on one side, diff ring can be attached and held easily for sanding smooth. The other side of the tool can be used as a diff stand, securely holding the ball diff and stabilizing it while tou insert the small diff balls and it also has a pin or a small block to hold the diff nut or screw.