Garmin VariaRTL515 rearview radar provides visual and audible alerts for vehicles approaching from behind up to 140 metres away.Key Features:Varia RTL515 is a smartphone compatible cycling radar and tail lightRearview radar with tail light offers awareness of vehicles approaching from behind up to 140 metres awayPairs seamlessly with your Edge bike computer and compatible smartphone as well as select Garmin wearables or the radar display unitWhen used with your compatible smartphone, the Varia app offers graphics - plus tone and vibration alerts - that indicate approaching carsWhen used with a compatible smartphone, Varia radar integrates with third-party apps such as Ride with GPS to overlay your maps with rearview radar alertsDaylight visibility up to 1 mile alerts motorists to your presence as soon as possible Compact vertical design mounts easily to most road-use bicyclesPeloton mode offers a low-intensity light flash that is perfect for cycling in groupsBattery life: up to 16 ho