When you change the Magneto side bearing, you have to replace the bearing track that comes with the new bearing. I used to grind it off (carefully), but its a bit tricky and easy to mess things up. This tool changes all that. It’s got spring loaded clamps, that when tightening the two bolts on either side, grip the sleeve on the inner edge. All thats left is to tighten the bolt on the top and it pulls off the sleeve.