1Accurate: Upgraded double sided printing size. The Inch and metric thread checker is an accurate and easy to use thread identifier for both nuts and srewbolts. The thread checker is especially well suited for distinguishing between similar inch and metric threads. 2Easy to Assemble: Each individual gauge features a male threaded stud on one end and a female threaded hole on the other. Conveniently assembled onto a wire loop, it's the perfect portable solution! 3Specification: There is a nut and srewbolt thread checker for each size in the same gauge, 26 male and female gauges, 14 inch and 12 metric gauges. 426 Sizes: Silver includes 14 inch size part numbers: 632, 832, 1024, 1032, 1/420, 1/428, 5/1618, 5/1624, 3/816, 3/824, 7/1614, 7/1620, 1/213, 1/220. Black includes 12 metric sizes part numbers: M4x0.7, M5x0.8, M6x0, M7x0, M8x0, M8x25, M10x0, M10x25, M10x5, M12x25, M12x5, M12x7 5Durable Material: Made of premium zinc material, this thread identification tool is durable, rustproof and has a long service life. It is a practical construction tool for workers.