InstallBay Speaker Polarity Tester / Phase Meter

The speakers in your stereo system should all be acoustically "in phase" with one another - cones moving in and out the same way at the same time - so the sound will have uniform strength and frequency response everywhere in your listening space. Install Bay's FH-168 phase checker can tell you if your speaker's wired correctly or needs rewiring. Play a test tone or repeating signal "pops" through the speaker, hold the FH-168 and its built-in microphone in front of the speaker, and the red and green lights will tell you what you want to know: a green light means it's in phase; a red light means it's out of phase. A yellow light warns you when the battery needs replacing.

What's in the box:

• Polarity tester
• 9V Battery (installed)