"Viking Horns" Brand New 4 Metal Trumpets Air Horn. Will produce a Loud Powerful Sound at 149 decibels. All the trumpets are chrome plated metal. Great for Car, Truck, SUV, RV, Boat, Pick-Up. Comes with a 12 volt electric valve (solenoid), mounting hardware, 1/4" OD high pressure hose, and installation instructions. Trumpet Sizes: 13-3/4", 11-1/2", 9-1/4", 7-3/4" with 3-3/4" front diameter each. REQUIRES AN ON BOARD AIR SYSTEM TO OPERATE  (which consists of air compressor and air tank)