Range: 4" to 20"/100 to 500mm Reads in Inch/Metric/Fraction Resolution 0.0005"/0.01mm (fractions in 1/64" increments) Dust water and oil resistant to IP54 standards Extra-long jaws which allow for increased measurement capability are etched with depth markings and have threaded holes for depth stop locations (1" and 1.5") to ensure proper measuring alignment 4" preset without the need for a master for internal measurements. Zero setting and reversible contact points for external measurements (can be used for some rotor and disc measurements) Hold function .