・ These flute countersink drill bit sets are machined from high-speed steels and are available in 6 different diameter sizes. Size - 6mm(1/4"),8mm(5/16"),9mm(3/8"),12mm(1/2"),16mm(5/8"),19mm(3/4") ・ 90° angle on the point for sharp and precise countersinking. The cutting edge is hardened and honed for sharpness. A Chatter-Free,five-flute designed with staggered cutting teeth arranged to insure free chip flow and rapid chatter-free cutting ・ Ideal for wooden planks,fiberboard,particleboard,plywood,plastic,aluminum board,PCB board and more ・ Great for Sinking 90 Degree Holes into Wood and Soft Metals Countersunk Screws and Fixings. Suitable for DIY,Home and General Building/Engineering Using ・ 1/4&Prime hex shank countersinks are fine for a quick drill. They don't slip in drill chucks. You can make deep countersinks easily by setting the countersink's depth stop to allow the countersink to drill more deeply into the worksurface Specification: ・ Material:High-speed Steel ・ Quantity:1 Set (6 Drills) ・ Length:48mm/1.88" Package included: ・1 x 6mm Drill ・1 x 8mm Drill ・1 x 9mm Drill ・1 x 12mm Drill ・1 x 16mm Drill ・1 x 19mm Drill