The Garmin Varia RearVue 820 represents the most powerful and precise cycling radar tail light Garmin has ever built, combining strikingly bright visibility with advanced vehicle detection technology to give riders greater awareness and confidence on every road and gravel ride. This is not just a tail light-it is a comprehensive rear awareness system engineered to keep riders informed and visible in real time. At the heart of the RearVue 820 is Garmin&&';;s most powerful radar yet, detecting vehicles approaching from up to 175 meters away with a wider field of view than previous generations. This expanded detection range delivers more reliable alerts earlier, giving riders critical extra seconds to respond to approaching traffic. Advanced vehicle tracking goes beyond simple detection-riders can see alerts distinguishing small, medium, and large vehicles, monitor lane changes, and assess threat levels when paired with compatible Edge cycling computers or the Varia smartphone app. The tail light delivers up to 2 kilometers of visibility, ensuring riders are seen by approaching vehicles long before they arrive. A dedicated brake light detects when the rider is slowing or stopping and displays a unique flash pattern-communicating deceleration to following traffic in the same intuitive way automotive brake lights do. Four light pattern options-day flash, night flash, solid mode, and peloton mode-allow riders to adapt to any condition, and custom patterns can be created directly in the Varia app. Alerts reach riders through multiple channels depending on their setup. Visual and audible alerts are available through the Varia smartphone app, compatible Garmin Edge cycling computers, and Garmin smartwatches. Select smartwatches add haptic and voice alerts for approaching vehicles-keeping eyes on the road rather than on a screen. With up to 24 hours of battery life in day flash mode, the RearVue 820 outlasts even the longest rides and multi-day adventures. The sleek, compact design and new seatpost mount integrates cleanly onto virtually any road or gravel bicycle, while compatibility with the Varia seat rail mount kit (sold separately) expands fitment options further. Simple, powerful, and intelligently connected, the Varia RearVue 820 sets a new standard for rear visibility and traffic awareness. Includes mounting kit and charging cable. Compatible with Garmin Edge cycling computers, Garmin smartwatches, and Varia smartphone app. Seat rail mount kit sold separately. Up to 24 hours battery life in day flash mode. Vehicle detection range: up to 175 meters. Key Features 175-Meter Advanced Radar Detection - Most powerful Garmin radar yet with wider field of view tracks vehicle size, lane changes, and threat levels 2km Visibility with Brake Light - Brightest Varia tail light ever with automatic brake light detection for intuitive traffic communication Multi-Device Alert System - Connects to Garmin Edge computers, smartwatches, and the Varia app for visual, audible, haptic, and voice alerts