Amprobe ULD-300 Ultrasonic Leak Detector Polyester 100% Made in the USA and Imported Senses pressurized leaks, detects electrical arcing, and finds failing solenoids, valves, and bearings Ultrasonic sensor converts ultrasonic frequencies to an audible range so they can be heard Detects any pressurized leaking gas, including chlorofluorocarbon (CFCs), hydrofluorocarbon (HFCs), nitrogen (N), carbon dioxide (CO2), and steam Parabola horn aids leak detection from a distance and in noisy areas Extension tube provides additional reach for access to remote leaks