DeWALT DW2535 Countersink Set, HSS, 3-Piece, For 3/8 and 1/2 in Drills and Drill/Drivers                       Drill, countersink and counterbore in one step. Four cutter countersinks and replaceable tapered drill bits provide great speed and finish. Universal 1/4 in hex shank locking system prevents slipping. Includes #6 (9/64 in), #8 (11/64 in) and #10 (3/16 in) countersinks.