For gaging standard pipe and pipe fittings! Use Vermont Gage pipe thread plugs to check tapered external pipe threads. Vermont Gage pipe thread gages are made to precise class X tolerances and come with Certificate of Accuracy. Add a taperlock handle to create a complete pipe gage assembly. Class X. NIST traceable. Tool steel; 60/62 Rc (Cold Stabilized). Taperlock Style. Certificate of accuracy included.