M Maximum efficiency: >=88% Wheel diameter: Approx. 20in Wheel width: Approx. 4in the rear drive is 170mm Size of controller:14.7cm8.3cm4cm Package included: 1 x Wheel 1 x Controller 3x Trigger Shifter 2 x Shifters 1 x Shifters Clip 1 x Binding Post (Yellow Box) 4x Ribbon.