The Blue Medium Diamond Wheel provides refined shaping for carbide and HSS gravers. The Medium Wheel shank is 2.35mm in diameter and easily mounts in a micromotor (like NSK EVO or Electer) or flex-shaft (Foredom) hanging motor. 25 x 2.5 mm wheel. For non-medical use only. Do not exceed 5,000 RPM when using this wheel.