The Timber Yew! bell is designed to alert other nearby trail users of your presence. Using a spring-loaded on/off switch, the bell can be turned on, ringing activated by the bikes motion, or it can be silenced when not needed. The Timber bell offers a friendly way to warn other trail users of your approach. Spring loaded piston on the on/off lever for smoother shifting Bolt-On bell Fits 35mm bars (includes shims for standard 31.8mm and 22.2mm bars) Quick release model uses quick-release O-rings to mount and fits 35.0mm to 22.2mm bars