1/4 20 UNC Class 2B & 3B Go Plug Gage Friction grip handle allowing the thread gage member to be reversed when one end becomes worn tool steel cold stabilized thread plug Rc 60-62 work plug handles can be marked with 15 characters at no additional cost Inch handles will be light blue metric yellow Certificate of Accuracy is included Certificate of Accuracy is included.Click HERE to read about additional Long Form Cert.