MPC Train Horn Kit - Triple Air Horns for Car or Truck. Includes 110 PSI Air System Separate Mounting Chrome Triple Train Horns (17", 15", 13" lengths) w/ 12v electronic solenoid included. All-in-one Air System w/ 110 PSI Compressor & 3 Liter Air Tank (Dimensions: 15.75" L x 5.25" W x 6.0" H) Kit includes a pressure switch (85 PSI on/105 PSI off), 12 ft of 1/4" air line, push button switch, *The compressor in this kit MUST be installed in a clean and dry location. Failure to do so will void the product's warranty.