Threaded Ring Gauge Long Form Calibration Certificate No Material Tool Steel Dimension Type Inch Gauge Type Go (Plus) Pitch Diameter 0.5875 in Pitch Diameter - Go Member 0.5875 in Thread Class 2A Thread Length 9/16 in Thread Size 5/8 In.-18 Thread Type UNF Compatible Holder Size 4T Finish Uncoated Gauge Design Adjustable Hardness RC 60-62 Included Certification Certificate of Accuracy with NIST Traceability Standards ASME B1.2 Tolerance Class X