Hex Coupler 6mm Bore Motor Hex Brass Shaft Coupling Flexible Connector for Car Wheels Tires Shaft Motor 8pcs

Was very good quality.

The product itself was OK. The packaging was very, very poor. The included M4 screws for tightening the coupling to the motor shaft were actually M3 screws. The M4 screw is for fastening the wheel to the end of the coupling. All parts, couplings and screws, were just loose in a plastic bag. As a result, one of the M3 screw was lodged into one the M4 hole. It was so deep, I can not get it out. So instead of 8 couplings, I now only have 7 useable ones.