Goldwood GT-1188 Piezo Horn Driver 1-3/8-18 TPI Makes an excellent low priced upper midrange/tweeter driver 1-3/8&quot; 18 TPI mount for easy connection to many popular horns Piezo drivers do not require a crossover and are an easy load for most amps Extremely fast transient response Internal protection circuitry handles up to 400 watts of continuous power