Leaks are quite common in pneumatic systems (controls, hoses, tools, fittings). Listen for the rushing sound of the leak! Large hydraulic leaks are obviously easy to see, but small ones can often be difficult. The AccuTrak® will allow you to hear these leaks with ease! Internal leaks in hydraulic cylinders can be detected using the touch probe. When testing for external hydraulic leaks use the yellow waveguide to protect any fluid from entering the sensor.