The Grainger Approved Gage Pin Set ZZ Minus is a set of precision ground steel pins used for calibrating gages, checking hole locations, and setting up inspection tools. The set contains 18 pins ranging from 0.4995" to 1.0005" in diameter, with a tolerance of +/- 0.00005". The pins are made from hardened steel with a black oxide finish for corrosion resistance. They come in a fitted plastic case for storage and portability. This pin set allows for precise measurement and calibration for quality control applications.