DGOL 3 inch Twist Knot Wire Wheel Brush 1 Pack + Wire Cup Brush 1 Pack with 1 4 inch Round Shank for Die Grinder or Drill,Wire Diameter 0.02 inch home2022 ensuring a quick and effortless A punch needle is ensuring a quick and effortless operation minor cuts THESE ARE STRONG AND THICK WIRES 5mm) These are quite strong and thick wires Shank diameter is 1 4" 1 4" shank diameter suit for most drills and die grinders Max operation speed(RPM) for wire cup brush is 4500 RPM Max operation speed(RPM) for wire wheel brush is 12000 RPM Twist knot wire wheel brush could last much longer time than normal wire knot brush We also supply other size like 3 4"