The Combination Drill and Tap Bit Set comes with 13 pcs of SAE and Metric sizes to fulfill multiple steps in a breeze. The tools are designed to drill, tap, and countersink through various rigid materials with ease, while the deburring feature cleans the holes smoothly and bits countersinks threaded holes. In addition, its High-Speed Steel improves the cutting performance of the drill and makes it more wear-resistant, prolonging its service life. These specialized countersinking drill bits can cut through aluminum, plastic, metal and much more to complete many different types of jobs. The bits are fast, and with multiple sizes available, it ensures proper hole sizing. The 1/4 inch (6.35mm) Hex Shank has a tapered end to assure over tapping is prevented and the back taper exceeds the tap to prevent over-drilling and damage to the thread. These bits come with a storage case and are provided in both SAE and Metric sizes engraved onto each piece for easy identification.