Please note: Horn is suitable for all cars without air supply system There are 4models to choose from (the fifth is a compressor, not a complete set of air horns, which is suitable for repair and replacement). IF your car is 1 2V ,please choose 12V air horn---IF your car is 24V ,please choose 24V air horn It can produce sound as loud as 150DB. The great powerful sound catches everyones attention Specification: Material: Zinc alloy Voltage: 12V or 24V Product size : 45 cm x 10 cm x 9 cm / 17.7 *3.9 *3.6 inches Hose inner diameter :0.7cm Package includes: 1x Single Trumpet Air Horn 1x Air Compressor 1x Air Hose 1x Bag of Fixings 1x instruction manual 1x Relay harness p.p1 {margin: 0.0px 0.0px 0.0px 0.0px; line-height: 19.0px; font: 13.0px Helvetica Neue; color: 000000} p.p2 {margin: 0.0px 0.0px 0.0px 0.0px; line-height: 19.0px; font: 13.0px Helvetica Neue; color: 000000; min-height: 15.0px}