Garmin Varia RTL515The Garmin Varia RTL515 is not your ordinary tail light. It's also a rearview radar that pairs up with your Garmin Edge bike computer or compatible smart phone to alert you of vehicles approaching from behind. It allows you to be more aware of your surroundings. With daylight visibility the Garmin Varia RTL515 lets approaching vehicles see you from up to a mile away. It's small, it's easy to mount, and it works with just about any bike. Features Rear view radar: lets you ride like you know what's coming. Multiple display options: Pair it with your compatible Garmin device, your phone or both. Varia(TM) app has you covered if you're using your phone as a primary or backup display. Daylight visibility lets approaching vehicles see you from up to a mile away. Small and easy to mount works with just about any bike. long battery life 16 hours of battery life in day flash mode. Specs Dimensions: 3. 9" x 0. 8" x 1. 6" (98. 6 x 19. 7 x 39. 6 mm)Weight: 2. 5 oz (71. 0 g)Modes: solid, peloton, night flash, day flash Lumens: 20 solid, 8 peloton, 29 night flash, 65 day flash Battery life: 6 hours solid, 8 hours peloton, 6 hours night flash, 16 hours day flash ANT+(R): Yes BLE: Yes Water rating: IPX7Viewing angle: 220deg | Garmin | Varia Rtl515 Rearview Radar Taillight Black