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 the confidence 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 bothering with the slower bolt-on Varia mounts. SAFE - The ATOP lacing system and rubber adapter pad provides a soft interface that won't scratch or wear your carbon or aluminum seatpost. SECURE - Ride confident 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.