Worm Wheel, Bore Diameter 12 mm, Bore Diameter Tolerance +/- 0.2 mm, Bore Type Plain, Face Width 18 mm, Gear Shape H4, Hub Diameter 40 mm, Hub Projection 15 mm, Material Aluminum Bronze, Metric Module Pitch 2, Number of Starts 1, Number of Teeth 30, Outside Diameter 66 mm, Overall Length 33 mm.