The Robinair 16451 Ultrasonic Sound Generator and the Robinair 16455 "TruTrak" Ultrasonic Detector form a non-invasive leak detection system capable of finding leaks in enclosures, such as buildings, vessels, automobiles, walk/reach-in freezers, or any other container that needs to be leak-free.
The 16451 Sound Generator is used to "pressurize" rooms and enclosures with its sound. This sound is above the human hearing range and cannot be heard. It can penetrate through minute cracks, even ones that are not directly behind the leak point, and exit through it. It can thus trace the path air, or water, will take to cause a leak.
The 16455 Detector receives the ultrasonic sound that escapes from the leak point, processes it, and displays its strength. The bigger the leak, the higher the volume in the headset.