This set pilot drills and countersinks at the same time, producing a faster finish. Heavy-duty design manufactured from carbon steel C45. Replaceable drill bits manufactured from high-speed steel. Drill bits can be adjusted and fastened with a hex set screw. For countersinking screw holes for flush fitting of screwheads in hardwood, soft wood and plastics. Fitted with quick change 1/4" hex. shank. Compatible with drills with a standard 10/13mm chuck. Features & Benefits:• Pilot drills and countersinks at the same time, producing a faster finish• Heavy-duty design manufactured from carbon steel C45• Replaceable drill bits manufactured from high-speed steel• Drill bits can be adjusted and fastened with a hex set screw• For countersinking screw holes for flush fitting of screwheads in hardwood, soft wood and plastics• Fitted with quick change 1/4" hex. shank• Compatible with drills with a standard 10/13mm chuckSpecifications:Tip angle: 118°Flutes: SingleMaterial: HSS and carbon steel C45C