5-40 UNC 3B NoGo Friction grip handle allowing the thread gage member to be reversed when one end becomes worn tool steel cold stailized 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 NOTE: selection of a 2B NoGo or 3B NoGo is based on your requirements. A 2B NoGo class plug will have a larger pitch diameter for the NoGo thread member only. The Go member is the same regardless of the class chosen. These plugs use a reversible handle design. Certificate of Accuracy is included.Click HERE to read about additional Long Form Cert.