bike bells YWS-981 Slide Bell Dome size : 28mm Material : Brass Top and Plastic Base Color : Polished Brass Clamp Size : 25.4mm~22.2mm(with gasket) Operation : Slide Knocking Special Design : 1. Easy to operate. 2. Special clamp, Easy installation. 3. Unique slide knocking device. product specifications Dome Size 28mm Material Brass Top and Plastic Base Color Polished Brass Clamp Size 25.4mm~22.2mm(with gasket) Operation Slide Knocking Special Design 1. Easy to operate.2. Special clamp, Easy installation.3. Unique slide knocking device.