PAC GM1A-RST OnStar SWC Retention RadioPRO Advanced Interface for GM VehiclesBRAND NEW PAC GM1A RST RadioPRO Advanced Interface for General Motors Vehicles Overview: RadioPRO Advanced has been engineered to save you time and seamlessly integrate into a vehicles databus system to retain features such as OnStar, steering wheel controls, factory amplifier, audio fade, rear seat entertainment system, and warning chimes. RadioPRO Advanced also improves the sound quality of warning chimes by playing them through the sound system or