The Mayhew 21224 Metric Pin Punch, 4mm is used to drive out and remove already loosened pins and keys after initial movement by a solid punch. Over all length: 6-Inch, Body size: 5/16-Inch, Body type: Hex, Blade width: 4mm, Bulk package, and 0. 1-pound. Comes with an unlimited lifetime . Mayhew stands for quality, dependability, and confidence. When the caliber of the tools is just as important as the skills of the professionals employed, businesses trust Mayhew to get the job done. Since 1856, our punches, chisels, and pry bars have been the go-to tools for OEMs and professional mechanics throughout the country. And while our company has grown to meet the needs of the professional market, as well as those of the do-it-yourself automotive enthusiast, our focus has never changed - leveraging our strength to build your business.