Suitable for manual countersinking in wood, plastics and metals. Plastic grip, 3 countersinking grips made of carbon high-grade steel with 1/4" hexagonal shanks. Diameters 12.7, 15.9 and 19 mm; blade angle 90°. Made of carbon high-grade steel, hardness HrC 53 ± 5. The bits can be clamped in a drilling machine.