This is a gear puller that pulls out gear bearings, pulleys, etc.You can hook your nails to either the outer diameter or inner diameter of your gear.Range of Use (Outer Diameter): 0 - 3.0 inches (0 - 75 mm); Reach: 2.6 inches (65 mm); Number of nails: 2 pieces; Tools: 0.5 inch (14 mm) wrench; Material: Carbon steel