Black Oxide-Coated Pin Gauge Set, Material Tool Steel, Finish Black Oxide, Diameter Increment 0.001 in, Diameter Range 0.2510 in to 0.5000 in, Gauge Type No-Go (Minus), Number of Gauges 250, Overall Length 2 in, Surface Finish Uncoated, Tolerance 0.0002 in, Tolerance Class ZZ, Hardness RC 60/65, Included Certification Certificate of Accuracy, Long Form Calibration Certificate No, Standards ISO 17025:2005, Dimension Type Inch