This radar works seamlessly with your Edge bike computer or compatible smartphone as well as select Garmin wearables. This smartphone app helps you increase your awareness by providing graphics — plus tone and vibration alerts — to indicate the position and speed of approaching cars. When used with a compatible smartphone, Varia radar integrates with your favorite apps, such as Ride with GPS to overlay your maps with rearview radar alerts. Easily mount this sleek, compact device on the seatpost of almost any road-use bicycle. The vertical design allows for better leg clearance and a perfectly comfortable ride. Time spent charging is not as good as time spent riding. Get up to 7 hours of battery life.