Clear and strong: Its 75 dB sound is quite loud and of a simple construction. The ringing is lively and lasts well 2s before fading, it is useful for pedestrians. Ultra-light: the doorbell is 41g. The doorbell is efficient, qualitative and above all very beautiful. the doorbell is made of metal. Do not tighten too hard otherwise the bell will no longer ring enough. The bell adapts to handlebars under 31.8mm. Functional and aesthetic, it is perfect for a classic bike such as vintage and road bikes, mountain bikes, scooters. The packaging includes the 6-sided wrench, two flexible stainless steel bands to attach your bell on the handlebar, rubber the bell is suitable for all bicycles. If the elements are missing in the coils, please contact us, we can make you a refund or send you a new doorbell. Easy to install: to fix the doorbell, you must stick the adhesive strip (l package included) on the handlebar, then attach the steel band (one is 8.5cm long and another is 11.5cm) between the bell and the handlebar. Finally, you must tighten the hex screws located on the upper part of the bell. This way your bell will be firmly attached to the handlebars. (Note: if you don't reassure, you can add glue to the screw.)