This board is spectrum analyzer which was already assembled , use LED  Green and Red color to show the level of signal. It has 8 frequency display and has 6 LED per frequency to show the amplitude.

Technical information:

- 8 Frequency display by LED 35HZ, 60Hz, 162Hz, 500Hz, 1KHz, 2.75KHz, 5.85kHz and 15.5kHz.
- 6 Level or 6 LED  -> 4 Green color and 2 red color.
- VR to adjust the amplitude of input freq to board.
- Need 12VDC dual supply +12VDC, 0VDC , -12VDC  1A.
- 2 PCB connection.
- PCB size : 11cm x 11cm x 5cm ( High at top of LED )