The GO-/NO-GO thread gauges offered by Gaugestools are precision inspection tools designed to verify whether internal or external threaded parts fall within defined limits. For external threads (screws), the “GO” ring gauge must screw fully through, while the “NO-GO” ring should enter no more than a few turns. For internal threads, the GO plug must pass through the full depth, but the NO-GO end must not. We are available in standard sizes (Metric, UN, NPT, BSP, ACME, trapezoidal etc) with ready stock and rapid dispatch, and custom production is also offered. For more infromation visit https://www.gaugestools.com/go-no-go-thread-gauge/