Tanfel #4-40 UNC GO NOGO thread plug gage ASME B1.20.1-2013 NIST traceable Hardened tool steel HRC 53-58. Polished finish Certificate of Accuracy (Included) Handle (Included) Case (Included) Taperlock design Right handed Class 2B Style: Class X Thread type: UNC Measurement System: Inch Condition: NEW