The CRICKET polarity tester is great for sound contractors, musicians, DJs and many others. Polarity, should it become reversed, can play havoc with a sound system. If two sources are emitting the same electrical or acoustic tone (frequency) and one of those sources is in a state of inverted polarity, those tones, when combined at a given point, will cancel each other. This severely alters the sound of a system. Polarity can be reversed while soldering cables, adding components to a sound system, reversing Banana plugs, or replacing a component in a speaker cabinet improperly, to name a few instances. The purpose of the CRICKET is to test the polarity of a sound system each time it is used to insure it is working properly. Battery powered CRICKET polarity/continuity test set makes it easy to determine whether every component in an audio system from patch bay to console to speakers is in or out of polarity. The CRICKET tests balanced and unbalanced cables of up to 2,000 feet in length. It will drive a snake (even one with transformers) and indicate which of a microphone's XLR connector pins is hot. The CRICKET can also plug directly into a speaker cabinet and drive the components. A glance at the CRICKET's red and green LED's can save hours of troubleshooting. No wonder it's an indispensable tool for sound system owners, operators, installers, and sound rental companies. The CRICKET polarity tester is a two-piece unit (send & receive). The send unit generates a pulse, which is sent through the speaker, cable, microphone or the device being tested. The receive unit interprets that pulse and indicates if that pulse is positive or negative. The bottom of each unit has a quick reference guide on how to understand the readings given. The CRICKET polarity test set is easy to use, necessary to own and not a lot of money. The CRICKET is suggested for anybody working with sound systems.