1.: Combination Drill & Tap Bit Set combines drilling, tapping, and countersinking into one tool, compatible with handheld drills, bench drills, and electric screwdrivers. It can drill, tap, deburr, and countersink holes in copper, brass, aluminum, metal sheets, and plastic simultaneously. This multi-functional tool eliminates the need for bit changes, saving time and enhancing work efficiency 2.Ergonomic Design: The drill bit set includes both SAE and metric sizes for high versatility. Each tap drill is clearly labeled for easy size selection. The convenient ¼-inch (6.35 mm) hex shank features a tapered end to prevent excessive impacts, and the back taper exceeds the tap to avoid over-drilling and thread damage 3.12 SAE and Metric Sizes: Can be used to tap various threads. 6PC SAE: 6-32NC, 8-32NC, 10-24NC, 10-32NC, 12-24NC, ¼-20NC; 6 metric-M3 x 0.5, M4 x 0.7, M5 x 0.8, M6 x 1.0, M8 x 1.25, M10 x 1.5; 1 piece-quick change adapter 4.Optimal Usage Tips: To achieve the performance with our drill tap set, follow these tips: Drill slowly and avoid excessive force to prevent damage. Always use ample cutting oil to ease the process and protect the drill. Focus on precise workmanship for clean results. Cut and retract a bit before recutting for better results. For tougher metals, pre-drill a pilot hole for guidance. These practices ensure efficient and effective use drill and tap set