Worm Wheel Bore Diameter 5 mm Bore Diameter Tolerance +/- 0.1 mm Bore Type Plain Face Width 5 mm Gear Shape HAT Hub Diameter 15 mm Hub Projection 7 mm Material Bronze Metric Module Pitch 0.5 Number of Set Screws 1 Number of Starts 1 Number of Teeth 40 Outside Diameter 21 mm Overall Length 12 mm