600% longer life & higher cutting speeds compared with conventional spiral auger bits. For precise, highly accurate, splinter-free holes in veneered plywood, as well as all natural hard, soft & end-grain woods. Specially milled spiral profile with screw point & lead-in cutters. Design for centred cutting action. With 10mm hexagonal shaft.6-piece set, 6-8-10-12-16-20x 230mm, in wooden storage case.8-piece set 10-12-14-16-18-20-22-24x 460mm, in wooden storage case.