This set of steel countersinks is used on steel, aluminum and other metals, plastic or wood. Enlarge or mill the holes, the deburring edges. An ideal drill accessory for any manufacturing workshop benefiting from the manufacturer's lifetime warranty. features: The set of four pieces includes bits for drilling pilot holes for 3 mm, 4 mm, 5 mm, 6 mm screws. Conical steel cutter specially designed for pilot hole. Handle depth adjustable with a wrench. Drill and mill for wood screws without changing the drill bit. The drilling length can be adjusted for screws of different lengths by simply loosening and tightening the adjusting screw. Chamfer is 5 flutes, in use, can discharge wood more quickly, disposable sink hole drilled smooth, perfect screw cap incorporated in the surface of the workpiece. Drill head: HSS 4241 with titanium coating. Heat treated and tempered high carbon steel with titanium coating for superior cutting power. Characteristics: Material: HSS Drill 4241 Black chamfer bit body: 45 steel Chamfer diameter: 15.8mm Size: 3mm x 60mm (L) / 4mm x 75mm (L) / 5mm x 85mm (L) / 6mm x 93mm (L) Tail: 1/4 stem Package size: 14 * 10 * 2cm / 5.51 * 3.93 * 0.78in Package weight: 115g Note: The color of the item may indicate an aberration of the view due to the difference in shooting light and monitor display. Package Included: 4pc * wood chamfer 1 pc * hexagonal rod