As functional as the bar and helmet-mounted mirrors are, there is a cost in aerodynamic drag and, for some reason, an insurmountable drag to the image of the road-devoted cyclist. Garmin preserves our pride and taps into some nifty tech with the Varia RTL515 Rearview Radar with Taillight, that packs significant features into a small package. Fitting onto most road bike seat posts, it tucks out of the way and is a rear-facing, red light flasher with a built-in automobile radar feature.The standard bulb modes are found here with 20 lumens on solid beam, 29 on night flash, and 65 on day flash, however, the Varia sends it over the top with a courteous peloton specific mode with 8 lumens of brightness. So keep your group ride safer without creating frenemies along the way.The Varia's primary feature is the radar that picks up traffic headed your way from 140 meters behind, and relays that information to your Garmin Edge bike computer or Varia app on a smartphone. The "car" shows a relative distance to help you judge proximity and gives you time to make lane adjustments or turn corrections. And the bulb provides enough visibility for you to be seen from up to one mile away.Battery life is impressive with 16 hours of on flash mode and six hours on solid, which will see you safely through most training rides.