Bar Fly 4 MTB Mount 35.0 and 31.8mmCompatible with Garmin Edge 200 500 510 800 810 1000 and Touring Touring Plus models and other computers Mountain bike specific design places cyclometer behind stem faceplate to add protection Computer face mounts level with bar stem for a cleaner look Now includes mounts for all these items: Garmin, Mio, Magellan, Wahoo, Polar, Cateye, Bryton, GoPro, Di2, and lights Absolute click when computer is locked into position 35. 0 and 31. 8mm diameter