Product Usage - -Suitable for drilling workpieces with hardness less than 25 HRC, such as carbon steel, iron sheets, insulation plates, PVC plates, wood panels, etc. . . Drill with chuck or connector. Product set - -4 HSS pieces built to drill holes with screws sizes 6, 8, 10 and 12. < p >How to use- -The default length can be adjusted for different screw lengths by loosening and tightening the grub screw. Adjustable depth - -Adjustable counter sleeve depth with wrench. Compatible with standard 1 or 4" shank. Steel Plywood - -Specially designed steel plywood for counterfeit holes or holes. Drill and countersink for wood screws without changing bits Features: Condition: New. Material: 4241 high speed steel. Color: as picture shown. Forest Size: 6, 8, 10, 12. 6: 2.38mm. 8: 2.78mm. 10 : 3.175mm. 12 : 3.56mm. Note: Due to the light and screen setting difference, the item's color may be slightly different from the pictures. Please allow slight dimension difference due to different manual measurement.