In addition to providing a display for your backup camera this mirror monitor also comes with auto-dimming and OnStar. This means that together with it's reflective abilities, it also dims reflected headlights automatically to reduce distraction to the driver. Being OnStar compatible, this mirror monitor will allow you to continue to enjoy all OnStar functions of your vehicle even after replacing your rear view mirror. ***Note: the monitor does not come with OnStar, rather is OnStar compatible. It won't give you OnStar functions if your vehicle doesn't have OnStar but will allow you to keep the OnStar functions if your vehicle does have OnStar.