This four piece train horn kit is simply the loudest in it's class. These horns are constructed of fiberglass reinforced ABS plastic which is lightweight and extremely durable. Without an adjoining minifold, the horns can be installed separately so the fit almost anywhere on pretty much every car or truck. The horns also feature power air flow technology that allows them to use very little air to create a loud sound, and let you honk the horn for longer. They not only have a genuine locomotive train sound but they are lightweight, extremely durable and sound at incredibly loud at as little as 100PSI.