The Bontrager SyncV2 lamp mount is an universal mount with an elastic strap, suited for the Bontrager ION headlights. Bontrager Sync V2 Bracket Features Compatible with all Flare taillights and Ion headlights from both Trek and Bontrager Fits most bars/seatposts (22.2-31.8mm), some helmets and Madone integrated seat masts Silicone body with a tooled adjustment handlebar clamp diameter 20 degree +/- side-to-side adjustment 16 degree seatpost angle adjustment integrated into SyncV2 bracket