Varia RearVue 820 features our most powerful and precise radar yet with a wider field of view, giving you more reliable alerts than ever before. The tail light offers up to 2 km (1.24 miles) of visibility and has a brake light that shows when you’re slowing or stopping. FEATURES: Powerful and Reliable Radar: With our most powerful and precise radar tracking technology, Varia RearVue 820 radar detects vehicles approaching from up to 175 meters (more than 190 yards) away with a wider field of view. Bright Tail Light and Brake Light: Our brightest tail light means you’ll be visible from up to 2 km (1.24 miles) away. A brake light detects when you’re slowing or stopping and displays a unique flash pattern. Advanced Vehicle Tracking: See alerts for small, medium and large vehicles, and see when a vehicle changes lanes, along with its threat level — when riding with the latest compatible Edge® cycling computers or the Varia™ app on your smartphone. Get Alerts Your Way: For visual and audible alerts while you ride, connect this radar to the Varia smartphone app, compatible Edge cycling computers or Garmin smartwatches. In addition to haptic alerts on your wrist, select Garmin smartwatches can also give voice alerts for approaching vehicles — this feature is currently available in the Garmin Public Beta program for select smartwatches 3 . Variety of Light Pattern Options: Ride with four different light patterns: day flash, night flash, solid mode and peloton mode, which helps preserve the eyes of riders behind you. Create your own custom light patterns in the Varia app on your smartphone. Compact Design: A sleek, compact design and new seatpost mount means Varia RearVue 820 fits cleanly onto almost any road or gravel bicycle and is compatible with the Varia seat rail mount kit (sold separately). SPECS: Dimension: 3.9” x 1.0” x 1.7" (98.9 x 25.9 x 43.2 mm) Weight: 3.2 oz (90 g) Light modes: solid, peloton, night flash, day flash Custom light mode configuration: yes (with Varia Mobile App) Radar-only mode: yes Lumens: 25 solid, 8 peloton, 40 night flash, 100 day flash Water rating: IPX7 Battery life: * 10 hours solid 15 hours peloton 10 hours night flash 24 hours day flash 30 hours radar-only ANT+®: yes (radar, bike lights) BLE: yes (radar, bike lights) Viewing angle: 220° Visibility distance: 1.24 mi (2 km) Rear tail light: yes Brake light: yes Rear radar: yes Lateral vehicle positioning: yes Vehicle size classification: yes Vehicle threat classification: Speed-, size- and lateral range-based Maximum vehicle detection range: 175 m Radar beam width: 60°