Class X No-Go Pin Gauge, Material Steel, Finish Uncoated, Diameter 0.3941 in, Diameter Increment 0.0001 in, Diameter Range 0.2811 in to 0.4060 in, Diameter Sub-Range 0.3901 in to 0.3950 in, Dimension Type Inch, Gauge Type No-Go (Minus), Included Certification Certificate of Accuracy with NIST Traceability, Surface Finish 4 Microinch or Better, Tolerance 0.00004 in, Tolerance Class X, Hardness RC 60/65, Long Form Calibration Certificate No, Overall Length 2 in, Standards ISO 17025