try these
http://www.griotsgarage.com/catalog.jsp?L1..._2520&SKU=77839NOW YOU CAN HAVE THAT WONDERFUL ITALIAN AIR HORN SOUND IN ANY VEHICLE
Years ago we offered those old traditional-style air horns. Problem was, you had to find a place for the compressor, then a place for the horns, then hook up the tubing... Work, work, work, not much fun at all. This modern version is so much easier to install. Everything is built into this compact unit! These are true Italian Air Horns, and as you may know, only the Italians know how to make super-loud, ear-piercing horns! These horns are easy to mount, and come with a relay, and easy installation instructions. Let's see: get taken out by a semi, or let them know you're there? You get to choose. Of course if you're going through town at midnight, blasting your horns, you deserve to get thrown in the poky. Super loud, rated at 139 db at 4 feet, 115db at 6 feet. Compact at 5 1⁄2" tall, 3 3⁄4" wide, and 4 1⁄4" deep. 12 volt, 10 amp with two tones at 530 Hz and 680 Hz. The air pump is steel and the horns are high-impact plastic. Small enough to mount on cars, trucks, boats, or lawn mowers! From our excitable and overly talkative friends in Italy.