The addition of XM Traffic, Weather and Radio services to your compatible Garmin makes driving with GPS essential, even if you know where you're going. With an optional subscription to XM NavTraffic, your Garmin notifies you of accidents, road construction, and weather-related traffic delays before they are encountered, and then offers an alternate route. XM WX Weather brings real-time, animated weather data directly to your unit, so you can steer clear of bad weather. Add XM Satellite Radio to the mix for hours of commercial-free listening enjoyment. XM reception requires this portable antenna s a subscription to XM service. The type of information GXM 30 provides to your unit, depends on your XM subscription package. Garmin's GXM30 XM satellite module is the best way to receive traffic, weather and radio feeds, through your car stereo. This smart antenna processes all the XM information it receives and sends the finished data to your unit for display.