Consisting of multiple carbon-steel gauges strung on a wire lanyard, the Fastener Thread-Identification Tool (a.k.a. Thread Detective, Thread Checker, Thread Verifier) is designed to be an accurate, easy-to-use way to identify thread sizes of bolts, nuts, and screws. The tool is available in "metric only," "inch only," and combination metric-inch, with thread size permanently stamped onto each gauge. Color-coded gauges or the dividers between the gauges allow for immediate recognition between inch and metric. The lanyard(s) can be hung on shop wall or stored in a toolbox or drawer.