Main size: 8mm shank tongue and groove router bits, 6.35mm tounge and grooving. Usage: The tongue and groove router bits set can be used for making cabinets, drawers, wooden doors, window cabinets, wooden floors and other woodworking projects, suitable for edge-to-edge splicing of wood Premium Material: Tongue and Groove Router Bit Set, Solid hardened steel bodies with clever Anti-Kickback design for safe installation, a dependable tongue and groove router bit for your woodworking projects Widely Applications: Great for kitchen and bathroom doors, office cabinets, flooring tables, bedroom shelves, outdoor frames, walls and more. Safety:Tongue and Groove Router Bit Set with anti-kickback design provide higher stability and less vibration.