Features: Gently rotate the control knob to adjust the output level. Different settings allow for customized audio performance, providing smooth and convenient operation. Connect the RCA output of this controller to your amplifier, and connect the car stereo’s RCA output to the input of this unit. Ideal for subwoofer amplifier volume control. Used to adjust an amplifier's power level, stereo balance, equalizer, or crossover volume from the dashboard or other remote locations. Adds subwoofer level control or helps balance multiple amplifier setups. Compact design allows for flexible mounting options, placing control within easy reach. Fine-tunes the volume of any RCA line-level signal. Simple plug-and-play RCA connections; no additional wiring required. Connect the RCA output of this controller to the amplifier, and connect the car stereo output to the RCA input of this unit. Specifications: 4 RCA ports: 2 RCA inputs and 2 RCA outputs Level control knob Frequency Range: 150Hz - 40Hz Volume Gain Range: 0dB to -12dB Dimensions: 48 x 56 x 41mm (1.89 x 2.2 x 1.61 inches) Material: Plastic Color: As shown in picture Package Contents: 1 x Controller Note: Light reflection and differences in display screens may cause slight variations in color between the image and the actual item. Measurement error allowed is +/- 1-3cm.