On the double rotor motor power coupling system existing now. electromagnetic coupling of the inner motor is the only way to transmit engine power to drive axle. And this leads to the low transmission efficiency when the vehicle is driven by the engine. Aiming at this issue. https://www.bekindtopets.com/mega-super-2-Button-Hand-Control-for-the-Mega-Motion-Lift-Chairs-ELEASMB7120027-save-more/