ITEM NAME:Set of 4 Carbide Tipped Cleaning Bottom Router Bit Cutter 6mm Cutting Dia, 8mm Description: Router CNC Engraving Wood Working Bottom Cleaning Bit - 8mm/ 0.315in Shank - 5mm/ 6mm/ 8mm/ 10mm/ 12mm 16mm/ 18mm Cutting Diameter. Industrial grade micro grain car.Shank: 8mm/ 0.315-in. Mainly used for cutting and smoothing a variety of materials from wood, plywood, MDF and other wood composites etc. Build-up & heat resistant polytef coating, anti-kickback design.