Kahlenberg Chimetone Air Horns all utilize more than one projector or “trumpet” in their design. These projectors each produce a different fundamental frequency which combine to produce powerful, distinctive, musical chords. To hear a Chimetone Air Horn is to realize that the sound of a vessel can be one of its most impressive aspects. The Model D-4A CH Air Horn is designed for the most discriminating yachtsman. It is made entirely of bronze and brass, and finished with the highest quality duplex nickel chrome plating.