ATOPLEE 90 Degree 3 Flutes Titanium HSS Chamfering Cutter Drill Bits End Mill Countersink,6pcs This set include: 6.3mm, 8.3mm, 10.4mm, 12.4mm, 16.5mm, 20.5mm. Chamfering tool is the best alternative to traditional bore chamfer. Material: HSS4241 Shank: round handle High precision and low roughness of the machined surface, strong applicability.