Gold Tone 3mm Shaft Bore Motor Flexible Coupling Coupler Product Name : Motor Wheel Coupling;Bore : 3mm/ 0.13" Screw Diameter : 3mm / 0.12" 4mm/ 0.12";Hex Head Opposite Sides Distance : 12mm / 0.47" Bottom External Diameter : 11mm / 0.43";Overall Length : 18mm / 0.7" Material : Brass;Color : Gold Tone Net Weight : 13g;Package Content : 1 x Motor Wheel Coupling