Worm Wheel Bore Diameter 5 mm Bore Diameter Tolerance +/- 0.1 mm Bore Type Plain Face Width 8 mm Gear Shape HA Hub Diameter 12 mm Hub Projection 8 mm Material Aluminum Bronze Metric Module Pitch 0.8 Number of Starts 2 Number of Teeth 20 Outside Diameter 17.6 mm Overall Length 16 mm