This device monitors the pressure in your air retract system and provides the following: An Accurate Digital (3 digit) Air Pressure gauge. Up to 175Lbs PSI Green LED display Allows you to set a minimum pressure level - If the air pressure in your air retract system drops below this minimum pressure level, your retracts will automatically be lowered. The system will also automatically lower you retracts in the event of a loss of radio signal. This is a great backup system that can save your airplane from air system failure. This unit hooks up to your air pressure system using an air system quick connect fitting (robart sytle) and connects between your receiver and your retract servo. Includes: Air Jockey Unit Air system quick connect fitting Male to Male Servo extension