Greenlee 1791AV Standard Round Knockout Replacement Punch, 1-7/8-Inch,Greenlee,1791AV" /> Round standard metal punch units are complete units consist of punch, die and draw stud Use with battery-powered, hydraulic, ratchet or manual drivers Properly assembled through pilot holes, they will make clean, fast and accurate holes Use with Greenlee die model number 1792AV Can be used on mild steel up to 10 gauge