Du-Bro Heavy Duty XL Dual Control Horn Part No: 3353. This "jumbo" size control horn has been designed for giant scale aircraft and it boasts two adjustment positions for a superior set-up. Made from high strength nylon, you will have the confidence you need when you hit the flight line. With a 1" \(25.4 mm\) square support plate and 1" \(25.4 mm\) long 4-40 socket head mounting bolts, your install will be rigid! The included 4-40 swivel ball link provides an easier fit and the strong connection you demand. Distance from the base outward to the pivot center is 0.625" \(15.875 mm\).