Wolo (845 Road Warrior DD Roof mount Truck Air Horn - 12 Volt Powerful 12-volt air horn that will produce the same high output, powerful deep sound that a big rig truck demands The beautiful chrome finish will look great on any truck, RV, van, etc Powered by a compact, heavy-duty compressor, which is maintenance free, no high-pressure on-board air tank required All metal construction throughout with a bright chrome finish so to withstand the extremes in all weather conditions and to provide years of dependable service Designed to securely mount on a vehicles roof with two sturdy mounting locations (horns base and front pedestal) that will eliminate vibration at high speeds and while driving on rough roads