SODIAL(R) Bicycle Accessory Bike Electronic Bell MTB Road Bike Loud Horn Cycling Hooter Siren 360 Degree Rotation red Made of durable ABS. Cool accessary for you. This bicycle bell can produce loud siren up to 90 decible. 360 rotation of the bracket. Suitable for handlebar diameter about 2.0~2.5cm. Easy to be fixed on the bicycle. Power by 2 * AAA batteries (Not included).