BenRan Cool All Copper Bell Mini Bicycle Bike Accessories Adjustable Safety Warning Loud Horn for Kids MATERIAL - Made of solid brass. LOUD SOUND - Compact but loud and long sound. It has a "knob" on a spring that you flip back with your thumb and release. It creats a loud "Ding" noise. ESAY TO INSTALL - Special screw design, easy to install on the handle bar of a bike. SIZE - Adjustable bell mounts to most handlebars. Handlebar dia.: 0.86"-0.98". IDEAL for GIFT - Vintage style and craftsmanship but practical. This bell brings back good memories.Ideal for gift.