Product parameters: RENYU 5PCS countersink drill bit set parameters include #4(7/64“) #6(9/64”) #8(11/64“) #10(3/16”) #12(7/32") and a 2.5mm Allen wrench, free storage box. Wear-resistant and durable: The counter sink drill bit's black chamfering part is made of carbon steel and the white drill part is made of 4241 high-speed steel, RENYU chooses the materials with care to create a professional and durable punching tool. Basic operation: The countersink drill bit drills both the screw holes and the countersink holes for the screw caps and keeps them on the same axis, so that the screw caps are below the plane of the board after screwing. Versatile use: 5PCS tapered Drill Bit is suitable for drilling machines with collets or joints, suitable for drilling holes in hard wood and wood ply. Storage and portable: RENYU has thoughtfully prepared a storage box for you to fit 5pcs countersink drills, which is convenient for you to quickly store it after work, portable and does not hurt your hands. RENYU 5PCS Countersink Drill Bit Set, #4#6#8#10#12 Counter Sink Drill Bit for Wood, Tapered Drill Bit with One 2.5mm Allen Wrench