Include 600-watt 4 channel amp, front and rear speakers, and all required wiring. Amplifier easily mounts inside fairing. Features r. e. m. i. t. circuitry for excellent FM reception from a Class D amp. Pre-tuned to factory radio, so zero adjustments are required, making installation very simple. Includes Ultra rear harness, which allows radio fader to control front/ rear levels. NOTE: For best performance, a radio reflash may be required.