Slotting Cutter Size: The shank diameter is 8 mm. The cutting height is available in four sizes: 2 mm, 3 mm, 4 mm, and 5 mm. The slotting cutter of the milling head is 31 mm, allowing versatile use with common routers. 2 mm Slotting Cutter Durability: The 2 mm slotting cutters are made of premium hard metal and feature precisely ground blades and sturdy ball bearings. These properties ensure exceptionally long service life and strength when working with hard and soft wood, which is essential for 8 mm groove cutters for most woodworking jobs. Use of the groove cutter set: 3 mm disc groove cutters are ideal for cutting straight grooves in narrow edges, the groove cutter set for tongue and groove joints, fixing plates, flat dowels and joints in sheet materials, hard wood and soft wood. They offer a wide range of uses for precise cutting and processing of wood. Precise groove cutter: High-quality carbide ensures maximum strength and durability of the cutters. The shank is manufactured with the highest precision and checked for tolerances and minimal vibration during rotation to ensure precise and quiet machining. Note: 4mm slotting cutter, please check the shank size of your cutter before purchasing to avoid defective order. All dimensions are detailed in the image description to ensure the cutters meet your needs.