Bike Computer Edge Mountain Varia Mount Tail Light Models ATOP Dial Security Varia Seatpost Under Saddle Mount Garmin Mount Dimensions: LxWxH 6 x 3 x 2 inches Compatible with the Edge 1000, Edge 1030, Edge 20, Edge 25, Edge 520, Edge 810, Edge 820, Edge Touring, and Edge Touring Plus Ideal for off-road riding Designed specifically for bikes with short stems Compatible with Garmin Edge 820, 520, 510, 500, 25, and 20 Replaceable Garmin insert with K-EDGE "Definitive Click" locking system Carbon bar safe. Fits 31.8 mm bars Weight: 48g Confidence – While your Garmin Varia or similar radar system increases your awareness and personal security when you're out on the road, our Garmin Varia mount builds on that confidence by providing a strong and secure mount for your Garmin Varia RTL510, Garmin Varia RTL515, or any other rear-facing device utilizing the Garmin quarter-turn system Note: Not compatible with the Garmin Varia RCT715 Adaptable – Utilizing the ATOP dial system, our Garmin Varia mount quickly and easily adapts with the turn of a dial to fit a variety of seatpost diameters and geometries: 27.2mm, 30.9mm, 31.6mm, D cross-section, or aero cross-section Quick change – The ATOP dial system quickly and easily installs and secures on any bike in your stable, eliminating the need for multiple Varia mounts or dealing with slower bolt-on Varia mounts Safe – The ATOP lacing system and rubber adapter pad provide a soft interface that won't scratch or wear your carbon or aluminum seatpost Secure – Ride confidently knowing your Garmin Varia mount is securely dialed-in with the strong and dependable ATOP lacing system without the fear of a failing single rubber band