HMT HSS SilverMax Weldon Twist Drill InsertFoam Set, 1/4, 5/16, 3/8, 7/16, 1/2"HSS XE twist drill bits with integrated Weldon shank for simple and accurate drilling in steel and fast tool changing. Removes the need for using a separate drill chuck in a Magnet Drill. Where drilling smaller holes in thick steel has been a long and time consuming job in the past, fitting the SilverMax Weldon Shank Twist Drills into a Magnet Drill can suddenly make the job far quicker and safer than struggling with a Pistol Drill and jobber drills.