Inch Thread Checker Set SWTC-S21 Gauge

The S & W Manufacturing SWTC-S21 Inch Thread Checker is a precision tool set that allows you to instantly verify and distinguish common Unified inch threads by inspecting both bolt and nut simultaneously. Constructed from zinc and black oxide finishes, the gauges are permanently stamped and mounted on a flexible wire loop to keep the set together while allowing individual use. It helps reduce threading errors, prevent wrong part substitution, and speed up inspection in shop, maintenance, or assembly environments.