They're about $50 from Courtesy Nissan. Go to Nissan motorsports there and click on Hella Air Horns. They give you a compressor, two trumpets, plenty of air hose, and a relay. I used the relay, but you probably don't absolutely need to. Go to [ www.zcar.com ] and the how to section to get an idea of how people installed them. The wiring isn't too difficult, but if you run into trouble, e-mail me at kick300zx@home.com Good luck, john