Preamer 5pc Industrial 5 Flutes 82 Degree Countersink Drill Bit Set Wood Metal Working Chamfer and Deburring Tool 5pcs 5 Flutes 82 Degree Hss Countersink Drill Bit Woodworking End Milling Tool Material:High Speed Steel .Size in the Picture.1/4" dia Shank For Easy Grip. Pack of 5 Type: Countersink Drill Bit ,Electric drill accessories This high speed Steel countersink has a 5 flute rose pattern for chatter free countersinking on , brass, aluminum, plastic, wood, and other materials.(Not for steel) Cut Quickly and Easily in Soft Metal, Wood, Rubber, Plastic and Other.