Enhance Air Flow and Faster Response This chrome look solenoid is used with air horns that require an on-board air system for 12 volt & 24 volt DC vehicles. When the vehicle's horn button is depressed, the solenoid becomes electrically energized, opening its chamber and permitting air from the tank to reach the horn. Air Valve is rated up to 150 PSI air pressure. Screws in to any horn that has a 1/4" NPT female thread, at air port. Compression fitting Power: 12V & 24 V DC Air Output (Thread): 1/4" NPT Compression Fitting :1/8" NPT-MALE Valve Max Air Pressure: 150 PSI