Shank diameter: 6mm; Cutting diameter: 3mm / 4mm / 5mm / 6mm / 8mm / 10mm / 12mm. Includes 5 double flute bits and 2 single flute bits, 7 types of cutting heads for different applications, meets a variety of cutting needs. These bits allow you to cut directly into a material to form a groove or dado (a groove across the grain of the wood) or to hollow out an area for a mortise or inlay. Use on CNC and other automatic routers as well as portable table-mounted and hand-held routers. Package Contents: 7 straight cutters with 6 shank mm.