This air horn measures 24 inches overall with a 6-inch bell and connects to the truck’s air supply through a 1/8-inch pipe port. It fits Mack applications. Mounted on the cab or hood, it forces compressed air through the resonating chamber to produce a loud warning sound for nearby traffic and pedestrians.Interchanges:Mack 38MR142Features24 inch overall length6 inch bell diameter1/8 inch pipe port connectionTech SpecsOverall Length: 28 in.Height: 12 in.Width: 6.75 in.Bell Diameter: 6 in.Pipe Port: 1/8 in.