High Quality: Made of CC45 steel, black hardened for a clean and durable finish Length Total Length: Approx. 58mm, Top Diameter 12mm, Top Length 25mm, Shank Length 29mm, Shank Diameter 6.3mm (1/4 inch); Ideal for Woodworking and Wood Carving: This rotary router bit set is ideal for sanding, polishing, shaping and polishing soft wood, plastic and rubber surfaces. Easy to Use: This rotary router bit set has a 6.3mm (1/4 inch) shank that fits all drill bits, don't worry if it doesn't fit your drill, so you can enjoy woodworking.