Disconnect the constant power supply connectors of the head unit (main deck), car navigation system, etc., and insert the red wire of the capacitor in between, connecting the black wire to the ground. Power enhancement can broaden the sound range, reduce noise, and improve sound quality. I am also listing a 47000μF amplifier capacitor in other items, so please take a look if you are interested. A simple instruction manual is also included. #Capacitor