Sound Sensation chooses to carry only the best in vehicle navigation. Alpine®'s current navigation system, PowerNav® is DVD-based technology that uses 1 disk for coverage of the contintental United States. Alpine does not require any activation or subscription fees. Alpine offers a variety of choices for monitors. Fixed screens, flip-up monitors with tilt and swivel movement or replace your existing radio/CD player with a head unit that does it all. Visit www.alpine.com for more info.