Each erosion resistant aluminum gauge features permanent engraved size markings and swivels on a metal rings for organized storage, loss while enabling fast thread pitches and diameter confirmation simplify industrial maintenance or household tasks by quickly matching nut / bolts to their exact thread specifications using this portable, not fade measuring set with error proof design Designed for mechanics, engineers, and enthusiasts, this essential thread measuring tool simplifies fastener identification in workshops, auto repairs, and home improvement projects Combining accuracy engineering with strong aluminum construction, this compact thread size identifier ensures years of stable service in harsh environments while optimizing workflow efficiency This 26 piece aluminum alloy thread checker gauge precisely identifies 26 metric ( M4x0.7 to M12x1.75) and royal ( # 6 32 to 0.5 20) thread sizes, offering a lightweight, rust resistant solution for quick nut and bolt verification with accuracy, Manufacturer: ZBIianxer