1. Copper alloy material- excellent resonance performance, achieving maximum sound volume 2. High-decibel ringing- clear and loud sound 3. adjustment of 18-25mm- universal compatibility for most bicycles 4. Quick installation design- no tools required, can be installed in seconds 5. 24/7 protection- waterproof and rust-proof for all-weather use Product name: Bicycle bell Applicable handlebar: 18-25mm Style: Color: Black Material: Copper Alloy + Aluminum Alloy + Plastic Package Contents: 1 x Road Bike Bicycle Bell Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.