: Nut and bolt is machined with carbon steel. bolt size and thread gauge can be installed in your toolbox or wall. We have provided you with reserved holes for hanging. No need to drill again. Bolt and Nut Identifier Gauge: Nut and bolt recognizes nuts and bolts in 28 sizes, 14 inch & 14 metric. Each size has an external thread for nuts and washers and an internal thread for bolts and screws, easily distinguishing between different nuts and bolts. Nut and Bolt : Bolt size and thread gauge bolt size and thread gauge is an accurate, easy-to-read, bolt and nut identifier gauge that quickly measures bolt length and nut diameter, easily separating metric from rigid thread sizes, saving you time and increasing your efficiency. Two Sizes: Nut and bolt gauge comes in inches and centimeters along the help you quickly identify different sizes of threads., Manufacturer: Littimoon