The Garmin Varia RVR315 Rearview Radar pairs up with your Edge bike computer to alert you of vehicles approaching from behind. This radar provides visual and audible alerts for vehicles approaching from behind up to 153 yards away. Combined with your Edge bike computer, or compatible smartphone as well as select Garmin wearables, it can help you increase your awareness by providing graphics, plus tone and vibration alerts, to indicate the position and speed of approaching cars. Easily mount this sleek, compact device on the seatpost of almost any road-use bicycle, its vertical design allows for better leg clearance and a perfectly comfortable ride, and enjoy up to 7 hours of battery life in a single charge. Enhance your riding experience with the Garmin Varia RVR315 Rearview Radar!