uxcell Robot Motor Wheel Coupling Coupler Connector 5mm Bore Product Name : Motor Wheel Coupling;Bore : 5mm / 1/2" Screw Diameter : 4mm / 5/32"(0.157");Hex Head Opposite Sides Distance : 12mm / 0.47" Bottom External Diameter : 10mm / 0.39";Overall Length : 17mm / 0.67" Material : Alloy;Color : Silver Tone Net Weight : 12g;Package Content : 1 x Motor Wheel Coupling