Leak Detector II is a portable operations support tool that detects ultrasonic vibrations generated by a gas or liquid leaking from pipes, as well as flaws or poor lubrication of bearings on rotary machines, and indicates the strength of the ultrasonic vibrations on an LED bar graph using numerical values and sound. It can be used not only as an equipment diagnosis tool, but also as an effective tool for energy conversation, environmental preservation and safety by detecting instrument air leaks.