Poly-Cal Electronic Caliper Range: 6"/150mm Accuracy: ± 0.008" Polycarbonate frame Resolution: 0.0005"/0.01mm (fractions in 1/64" increments) Absolute/Incremental measurement 4-way measuringTire Tread Gage For tire thread thickness measurement Spring-loaded and hold measurement button for ease-of-use Range: 1"/25mm Resolution: 0.0005"/0.01mm (fractions in 1/64" increments) 2.1" base 0.95" diameter rod