Integration with todays advanced vehicle systems like databus-controlled amplifiers can be difficult, if not impossible. AmpPRO SUB products like the APSUB-CH21 from PAC Audio seamlessly integrate with the databus allowing for full control and optimum sound from a factory radio when adding aftermarket subwoofer amplifiers. You control it from the factory radio, and it integrates with and optimizes factory EQ settings. Easy, plug and play installation means there are no permanent modifications to the vehicle.