Vermont Metric Thread Plug Gage Assembly, GO/NOGO, Vermont's Thread Gages allow you to inspect the pitch diameter and the functional thread for internal threaded products. All stock Metric Thread Plug Gages are made to Class X tolerances per ASME B1.16M (Metric M Series Screw Threads). A Certificate of Accuracy is included with each gage. Available in 6H, and each Thread Plug Gage is marked with nominal size, threads per inch, class of fit and pitch diameters. Features include... M39.0 x 3.00 Threads GO and NO GO Set Certificate of Accuracy included Select Trilock Plug or Set Plug from Pull Down Menu. Trilock Plug 6H... GO Gage Length: 31.8mm NO GO Gage Length: 22.2mm GO Pitch Diameter: 37.051mm NO GO Pitch Diameter: 37.316mm Set Plug 6g... GO Gage Length: 73.0mm NO GO Gage Length: 47.6mm GO Pitch Diameter: 37.003mm NO GO Pitch Diameter: 36.803mm