Wear Check Plug for Go Thread Ring Gage to calibrate thread 1.00UNM (M1.0 x.25 ISO-2) Thread Precision Thread Gage made of High Speed Steel then hardened. The picture is of the gage in our stock. Brand is; MiniTaps made to our specification in Switzerland. A gage certificate with our factory measurements is included with this gage. Any questions please call or email.