Style:Rearview Radar With Tail Light See and be seen with Varia RTL515 rearview radar with tail light. It pairs with your Edge bike computer, other Garmin device or compatible smartphone to alert you of vehicles approaching from behind up to 153 yards (140 meters) away. When used with your compatible smartphone, the Varia app helps increase your awareness with vibration alerts and more. With daylight visibility up to 1 mile, motorists will be able to see you from a distance. The radar’s compact vertical design allows for device mounting on most road-use bicycles. And peloton mode provides a low-intensity flash that is kind to other riders’ eyes when riding in a group.