TECHNOLOGY: Works seamlessly with your Edge(R) bike computer or compatible smartphone Varia(TM) app helps you increase your awareness by providing graphics, tone alerts and vibration alerts that indicate the position and speed of approaching cars Varia(TM) radar integrates with apps such as Ride with GPS to overlay your maps with rearview radar alerts Up to 16 hours of battery life in day flash mode and up to 6 hours in solid mode USES: Rearview radar provides visual and audible alerts for vehicles approaching from behind up to 153 yards (140 meters) away Alert motorists to your presence as soon as possible with daylight visibility up to 1 mile SPECIAL FEATURES: Easily mount the sleek, compact device on the seatpost of almost any road-use bicycle Features multiple modes, including peloton mode, which provides a low-intensity flash that is kind to other cyclists' eyes when riding in a group