Its tool versatility results in increased productivity, less tool changes, and longer tool life. It performs exceptionally in high-speed machining and full diameter milling as well as produces excellent surface finishes.4-Flute - Variable Helix - 3500 Fury HP End Mills, FC20, RH Spiral, Corner Radius, Standard, 3/8 The 3500 Fury is stocked with FC-20 coating..