Vixen Horns Loud 135dB 3/Triple Trumpet Train Air Horn with 12V/24V Electric Solenoid Chrome VXH3311C This product requires an Onboard Air System Color: Chrome, Ultra loud Construction Metal chrome trumpets 12V/24V Electric Air Valve (solenoid) Horn Size 11.5, 9, 6-&frac12;, 3-&frac34; dia. ea inches