Vermont Metric Thread Ring Gage Set, GO/NOGO, M39.0x2.00 6gVermont Metric Thread Ring Gage Set, GO NOGO, Vermont's Thread Gages allow you to inspect the pitch diameter for threaded products. All stock Thread Ring Gages are made to Class X tolerances per ASME B1. 16M (Metric Series Screw Threads). A Certificate of Accuracy is included with each gage. Each Metric Thread Ring Gage is marked with nominal size, class of fit and pitch diameters. Features include M39. 0x2. 00 6g Threads GO and NO GO Set Certificate