Item Description: Condition: Brand New Material: ABS plastic+Electric Parts Measurement: 54mm*50mm*20mm Black: GND(ground)- Red: 12V+ Blue: Positive output Effect: First, eliminate the car sound of the current noise Car is not activated when the car sound no noise, the car starts after the car sound noise, this phenomenon is mostly due to car electrical appliances on the car audio power interference caused by the installation of power filters can eliminate these noise. Second, eliminate the reverse as the screen Germany Department of cars and the United States Department of cars in some models, after the engine started, the output voltage interference is large, to the reverse light power supply is not pure DC power supply, but superimposed a pulse signal in the above, if the conditions available oscilloscope test, Found to be a square wave-like signal. If the reversing camera without a filter, the camera power supply line directly on the reversing lights, because the working voltage is very unstable lead to the camera work is not often, the output of the video signal is not normal, so the host is to see a serious Interference, jitter, or do not switch the reverse picture. Third, the elimination of HID lamp ballast electromagnetic interference HID lamp ballast by generating a momentary high voltage to light the lamp, will produce electromagnetic interference, by installing the power filter, you can eliminate this interference. Package Included: 1 X Car Audio Noise Filter