Tractor air horn kit fits New Holland Massey Ferguson Case Ih etc. Kit can be used when air brakes plugged in or out. Horn Tech air horn (very loud) plus mounting brackets.
3m 6mm pipe plus connectors plus Pcl fitting. 2m 2 wire cable to connect to horn switch 12v. Tractor air brake T piece plus Pcl fitting. Air Brake plug when trailer brakes not in use.