MMdex 3-Pieces 1/4'' Hex 5 Flute 90 Degree 1/2'' 5/8'' 3/4'' Countersink Drill Bit for Wood Metal Quick Change Set (Style A) 3 size:12mm 16mm 19mm, Shank diameter: 6.35mm (1/4 inch hex shank),angle:90 degree Applicable scope:suitable for wood plastic cutting chamfering etc Five Flute Chamfer Debur Countersink Carpentry Countersink Drill Bit Set 5 Flute Counter Sinks