The HIKMICRO Acoustic Leak Detector AD21 is a high-performance device designed for technicians and plumbers to find leaks in plumbing, water service, and residential or commercial properties. The device has four ranges of selectable digital bandpass filters, and the amplification is up to 80 dB. The filtration and amplification of the sound frequencies can help you locate the leakage points accurately. It can be widely used with the handheld sensor and pick-up sensor correspondingly. Furthermore, it can detect ignored leaks, reducing resource waste and property loss.