The Bendix+ PH-2 air horn provides a warning signal of greater volume and farther carrying qualities than usually found on automotive vehicles. The horn is designed on the principle of a vibrating diaphragm. The horn consists of die cast bodies, diaphragms, and two chrome plated horn bells, with the bells in a horizontal position. Two types of operating valves are commonly used, the foot-operated horn valve and the hand-operated horn valve. Each of these valves have a built-in strainer.