Hella 12V Triple-Tone Air Horn Kit Three red horn trumpets Comes with a high performance compressor with relay and mounting brackets Melodic Horn features change-over switch on compressor for selecting melodic or triple-tone sound Frequency (Hz): 880 High-Tone / 820 Middle-Tone / 780 Low-Tone Voltage (V): 12V - Sound Level (Db (A)): 118