Fowler 74-150-005 Electronic Rotor Gauge Measures most rotors while the wheels are still mounted on the vehicle Range: 0-3.25"/0-82.5mm; Resolution: .0005"/.01mm (fractions in 1/64" increments) Solid 1 piece construction Water resistant to IP54 standards Twin conical anvils with the ability to measure low points on both sides of the rotor