The Garmin Varia eRTL615 rearview radar provides you with extra safety while on the road. This battery-free rearview radar made just for your eBike, detects approaching traffic from the rear and displays it onto your compatible device. A built-in taillight makes you more visible to those driving behind you, with a daytime visibility of up to 1.6km (1 mile) away. | Garmin Varia eRTL615 Rearview Radar with Tail Light