I got the 4 inch, big enough to pull this fan (from an AC condenser) off the motor. It was stuck pretty bad, I thought, but (after I sprayed some oil in it and let it sit) it came off just like that.If you don't know what these things do, this is what they do: the three claws pull (on the fan, the bearing, etc.), while the center threaded axle pushes (against the axle the fan etc. is on). You simply put the axle up against each other, maneuver the claws around the object you wish to remove, and