One of the new Varia line of smart cycling devices from GarminFirst rearview radar system for bikes that warns of vehicles approaching from the rear up to 140 metresWorks independently or wirelessly connects with compatible Garmin Edge cycling computersEdge computer or handlebar-mounted Varia head unit indicates when one or more vehicles are approaching from the rearRiders alerted to relative speed of approaching vehicles and how close they areTail light unit brightens and flashes to notify approaching traffic of a cyclist aheadVehicles approaching from the rear is the number one cause of bike/vehicle fatalities in the United StatesBIKE RADAR KEY FEATURES:APPROACHING VEHICLE INDICATION - The Radar Display Unit (RDU) and compatible Edge cycling computer indicate up to eight approaching vehicles from behind, giving the cyclist information about the distance and rate of approachRDU informs the rider with an LED interface; Edge devices use an overlay of the current data screenAUTOMATIC ADJUSTMENTS - The tail light brightens and blinks when approaching vehicles are detected for an extra measure of safetyTHREAT LEVEL INDICATOR - Indicates the relative speed of approach and distance of one or more vehicles at a timeTail light only version includes: Varia radar tail light (RTL 500), Varia seatpost quarter-turn mount, Varia universal seatpost quarter-turn mount, microUSB cable, manuals