Specifications: Length-18cm(7.0″); Horn ball diameter – 5.5cm(2.2″); Metal mouth – 7.3cm(2.9″). Mounting dimensions: Handlebar diameter – 2.22 cm(0.87″).Superiority: The front section of the horn is made of a sturdy aluminum alloy to ensure durable and non-rust. The rubber ball of the horn is made of flexible rubber to ensure non-broken. EASY INSTALL : Just use a hex key/screwdriver (not included) to tighten the screws, easy to install and remove from the handle bar of a bike.Package Includes: 1 x Horn, 1 x Mount Clamp