"BIG BAD MAX has a sound chamber designed to create a deep big rig sound, three times (3X) louder than a factory horns. Works on all 12-volt vehicles: cars, trucks, motorcycles, boats and etc. The one-piece patented design requires no hoses like conventional air horns. Easily installs with one bolt that is provided, transfer the factory horn wires to BIG MAD MAX’S compressor and the installation is complete. Built with a heavy-duty compressor that is maintenance free assuring years of dependable service. The housing is made from super strong ABS plastic with a black stealth finish. If you want a deep sounding powerful air horn sound, BIG BAD MAX is the horn for you! 123.5 Decibels - 320 Hz, measures L 5 ¾ inches x W 3 ½ inches H 4 ⅝ inches. 30-amp relay is included. Single."