The loudest horn on earth! This kit is all you will ever need to be heard for miles. It includes everything you will need and only the best components are included. This is an actual train horn and is still in use on many locomotive train engines nationwide. The 5 aluminum kettle-drum bells and dual-disk diaphragms produce the loudest, clearest, locomotive horn sound possible! From the railroad straight to your truck, this is the real deal. This is the loudest train horn you can put on your car or truck. This air horn can be heard from miles.