000-120 2B Plug Gage set Go and No-Go set members Gage UNS stands for (American) “National Standard” miniature Thread series. This gage set consist one each of Go #1639 and one "No-Go" #1640. Precision Thread Gage made of High Speed Steel then hardened. Standard fit is 2B Picture is representative of part. Brand is;" MiniTaps" made specifically for us in Switzerland. Long form cert available for additional cost.