Pipe Thread Ring Gauge Long Form Calibration Certificate No Material Tool Steel Dimension Type Inch Gauge Type No-Go (Minus) Pitch Diameter 2.7526 in Pitch Diameter - No-Go Member 2.7526 in Thread Class 2A Thread Size 2 1/2 in 8 Thread Type NPSM Finish Uncoated Hardness RC 60-62 Included Certification Certificate of Accuracy with NIST Traceability Standards ASME B1.20.1 Tolerance Class X