The volume knob increases the amplification of the disruptive magnetic field. The quick select buttons on the CD player (buttons 1-4) send the spoofing signal to the wheel assigned to each button (i.e. button 1 is pegged to the front left wheel, button 2 rear left, button 3 front right, button 4 rear right). In mode 2 quick select buttons 5 on the CD player switches the hack into mode 1 (key fob control).