This 4 trumpet air horn kit includes four horns, a solenoid valve, a 1.6-gallon air tank, a compressor, and air pipes. It features an auto-inflating compressor for quick horn response. Made with rust-proof materials. Ensuring safety in any weather and effectively alerting others on the road. The compressor operates automatically, inflating when tank pressure drops below 90psi and pausing at over 120psi to prevent overpressure. A sensitive pressure gauge monitors the tank, and an upgraded leak-proof structure ensures reliable horn activation with minimal delay or malfunction risks. The upgraded PA pipe withstands temperatures up to 120℃, while the motor's thermal control switch automatically activates at 100℃ for protection and resets after cooling. Equipped with fuses for compressor protection and a tank drainage plug for easy removal of accumulated water. Thick and shock-absorbing rubber pads can be installed between the air tank's bottom bracket and the vehicle to secure the tank firmly and reduce noise caused by vibration during driving. The train horn kit includes screws, bolts, fuses, and other accessories needed for assembly, along with a detailed instruction manual.