This product is an audio common ground isolator, which effectively suppresses the noise caused by the common ground for the and the receiving device. Main Function: Eliminates current noise. The common ground isolation audio transformer eliminates current noise caused by AUX common ground. The output and output ground lines are isolated by the transformer, eliminating common ground. This product can only the noise and current sound generated by the common electricity, and can not the noise caused by other reasons, so you need to confirm of the noise yourself. High sensitivity and high fidelity, 10-20dB higher sensitivity than similar low-end , full tone, quality. Circuit design: Stereo dual-channel design. Determine if noise is caused by common ground: 1. Use the earphone to connect with the car MP3 and car navigation AUX (3.5mm interface). If the sound heard from the earphone is no noise at this time, it can be confirmed that the noise of the car device 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, MP3 is not connected to any power source on the car, such as a telephone), and the AUX of the car center console, and play the music of the mobile phone. Noise can confirm that the noise was caused by the common ground. 3. Computer, amplifier, stereo, CD: Use a passive headset to plug in the computer to hear if there is noise, use the phone to plug in the amplifier, audio audition, if there is no noise, the basic judgment is caused by the common ground. 4. After starting the car, the installed amplifier has a current sound. In some models, the throttle is larger and the current is louder. This product can solve this problem. 5. There is a current soundbetween the amplifier and the speaker or the sound. This product can be installed between the amplifier and the speaker. Color: Color Random Material: PCB+Components Package Contents: 1*Audio Isolator Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.