US PRO Tools 2pc Metric & SAE Imperial Drill Gauge Set, Hole Sizer Set 2276. This set is designed for measuring twist drills and other small items. It includes one gauge with etched metric graduations from 1 - 13mm and another with etched imperial graduations from 1/16" - 1/2". Both gauges are made from tempered stainless steel for durability and accuracy. The high quality Tools Drill Bit Gauge Size Checker is suitable for various applications.