Vermont Class X Trilock Plug Gage AssembliesVermont Class X Trilock Plug Gage Assemblies When you need to inspect large diameters, Vermont's line of Trilock Plug Gages are your best solution. These GO NOGO Plug Gage Assemblies include a Plug Gage member on each side, and are attached to the Trilock handle with mounting bolts. Included with the pricing is 1 line of custom marking, up to 25 characters. When ordering, Select Size Range from pulldown menu. After order has been placed, we will email