The Hillman Horizontal Bolt & Nut Gauge will help you quickly identify the most common size nuts & bolts in one compact and easy-to-use check center. Now you can know with certainty what size bolt or nut you have in your hand. No more guessing! Also known as a Thread Verifier or Thread Identifier, the Bolt & Nut Gauge is a must have for any shop, garage, or manufacturing facility. The Gauge has 26 female threaded holes (12 metric and 14 standard) for checking bolts or screws, and 26 male threaded studs (12 metric and 14 standard) to identify nut sizes. The bottom edge includes both a metric and standard (fractional) scale for checking diameter & length. It is made from 19" long by 3-1/2" wide by 1/4" thick annodized aluminum plate. It includes a pair of angle brackets and is pre-drilled for easy installation on a work bench or wall.