1Made of high quality GCR15 bearing steel material, high hardness 2Can be used as a standard measuring tool for holes 3Suitable for high-tech fields such as electronic boards, circuit boards, molds, accuracy machinery manufacturing, etc. 4Mainly used to measure the size, distance and depth of the hole. 5Including 50pcs pin gauges with a wood box which is from 4.5mm to 4.99mm