Garmin GTM 10 FM Traffic Receiver Traffic receiver picks up real-time traffic information from select FM broadcast stations in U.S. and Europe Converts data into color-coded maps on compatible Garmin GPS navigators and displays traffic hot spots Analyzes information and automatically calculates and suggests alternative routes to avoid traffic jams Silent FM data channel doesn't interfere with music or talk programming; requires service subscription Compatible with Garmin Nuvi and StreetPilot 2720, 7200, 7500, and c340; 1-year warranty