Feature:

1. Main Volume: This is the Master Volume that controls the overall volume of all zones.
2. In Boat and Tower Zone Volume: Adjusts the volume of the tower speakers (outside ring) and the volume of the in boat speakers (inside knob).

 You can set these levels to whichever volume you prefer and use the master volume for overall control.
3. Subwoofer Volume: Independent Subwoofer volume control.
4. Microphone: Independent Talk Back Microphone volume control.
5. Aux/Main Switch: Auxiliary input or main input selection switch.
6. Equalizer Adjustments: These 4 controls adjust the four separate frequencies (bass, mid bass, mid, high) Offering 12 dB of cut/boost.

The outside ring adjusts the frequencies for the tower speakers (6a) while the inside ring adjusts the frequencies for the in boat speakers (6b). 
7. Auxiliary Input: 3.5 mm aux input jack for MP3 player or additional source.
8. Boat Link™ 3.5 mm aux output jack: For linking with other WS-420 equipped boats.
9. Microphone Input: Microphone input for Wet Sounds talk back microphone.
10: Input Gain:
11. Main Input Sensitivity Gain adjustment.

12. Auxiliary Input Sensitivity Gain adjustment. NOTE: If you are not an experienced audio installer, it is recommend to leave these adjustments in the pre set factory position.
13: Illumination: WS-420SQ illumination comes pre set in blue illumination If you would like to change to red. Remove jumper and position to red.
14: Ground Isolation: Occasionally alternator whine may appear in your system if you source unit and amplifiers may have different grounds. You may use the isolation jumper to eliminate the noise. Please make sure unit is off when adjusting the jumper.

Spec.:

1.Bass Equalizer Frequency:100 Hz,Mid Bass Equalizer Frequency:300Hz,d Equalizer Frequency:2KHz,Hi Equalizer Frequency:15KHz

2.Parametric Equalizer Range:+ 12 dB,S/N Ratio:80 dB REF 1V Input

3.Frequency Response:10 Hz - 40 Khz, -3dB

4.Maximum Output Voltage:5V RMS,T.H.D.:0.05%

5.Input Impedance:20 K Ohms,Stereo Separation:80 dB/1 Khz,Operational Voltage:11 - 15V DC, Negative Gnd