Item Type: Car Audio Stereo Isolator Material: ABS Determine if the noise is caused by ground: 1. Use the headphones to connect with the car MP3 and the AUX (3.5mm interface) of the car navigation, if the sound heard from the headphones is not noisy at this time, it can be confirmed that the noise of the car equipment is caused by the common ground. 2. Use the audio cable to connect the battery powered mobile phone, or MP3 (note that the mobile phone and MP3 are not connected to any power supply on the car, such as the telephone) to the AUX of the center console of the car, and play the music of the mobile phone, so that there is no noise, you can confirm that the previous noise is caused by the common ground. 3. Computer, power amplifier, audio, CD: Use passive headphones plugged in the computer to listen to whether there is noise, use mobile phones plugged in the power amplifier, audio audition, if there is no noise in the two separately, the basic judgment is caused by common land. 4. After starting the car, the installed or modified power amplifier has a current sound, and some models will also have the larger the throttle, the greater the current sound, this product can solve this problem. 5. The laptop is connected to the projector at the same time to the power amplifier to produce noise, you can connect the laptop to the adapter power supply or use the battery, at this time unplug the power amplifier noise disappear, or unplug the projector The same noise disappears, then you can add a common ground isolator between the headphone hole of the computer and the power amplifier to eliminate the noise. Package List 1 x Car Audio Stereo Isolator 1 x Audio Cable 1Efficient Noise Isolation: The noise isolator can effectively reduce the noise and noise in the car stereo, so that the sound quality is purer. 2Multi Functional: Suitable for car navigation GPS and other devices, including one AUX channel, can connect a variety of audio input sources. 3Current Sound Eliminater: The board is equipped with a current acoustic filter, which can effectively eliminate the noise caused by power interference. 4Anti Interference: Built in high efficiency anti interference chip, effectively resist external interference signals, ensure stable sound quality. 5Clear Sound: Enjoy clearer, cleaner sound quality from your car stereo system with the help of this isolator, which reduces noise and static for a better listening experience.