20pcs Ball Nose End MillsYeeco 1/8" Double Flutes Ball Nose Carbide Engraving Cutter CNC Router Bits Spiral Set Tool , 3.175mm 22mm Bullet Point Shank diameter: 3.175mm Cutting diameter: 3.175mm Cutting edge length :22mm Item Length: 38.5mm MAINLY USED IN CUTTING AND ENGRAVING---- The Ball Nose End Mills are high-density polished, wear-resistant, high temperature,High cost-effective, improve efficiency,so they are wide Range applications: Wood Acrylic, PVC, Nylon, ABSResin, Most plastics and So On