ProFit QLH1MPCT 5/16-Inch Hex Bar with Integrated HSS Center Drill Short for MP Hole Saws, 5/8-Inch - 1 3/16, Silver Integrated CT center drill Quick Lock System - allows you to change between hole saw sizes and styles in seconds Ability to Enlarge and existing hole and drill at an extreme angle with ProFit's Quick Lock Arbor