Feature: 1. Extremely Simple Operation: Easy to use, just plug and play, no battery needed. Small and portable, this noise isolator doesn't take up much space and it's easy to take away. 2. Clear Music Enjoyment: Eliminate the humming noise caused by the ground loop when the audio source and (some car speakers/home audio systems) use the same power supply, so as to achieve clear music enjoyment. 3. Compatible Models: Works with any portable device that has 3.5mm audio jacks, for your car audio system, home stereo, when grounding issues persist. 4. Ground Loop Noise Isolator: This product is an audio common ground isolator, which is effective for the noise caused by the common ground between the audio source and the receiving equipment. 5. Satisfaction Guarantee: We strive to provide each customer with the highest standard of customer service to ensure you have a pleasant shopping experience. If you have any issues, inquiries or need assistance, please feel free to contact us directly. Specification: Interface: 3.5mm audio port Colour: Black Material: ABS Line length: 30cm Product weight: 20g Product size: about 60*22*13 mm/2.36*0.87*0.51inchTo determine whether the noise is caused by common ground: 1. Use the headset to connect with the car MP3 and the AUX (3.5mm interface) of the car navigation. If there is no noise from the sound from the headset 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 should not be connected to any power source in the car, such as a telephone) to the AUX on the center console of the car, and play the music of the mobile phone, so that there is no noise. , it can be confirmed that the noise in the past is caused by the common ground. 3. Computer, power amplifier, stereo, CD: Use passive earphones to plug in the computer to hear whether there is noise, and use the mobile phone to plug in the power amplifier and stereo to audition. 4. After starting the car, the installed power amplifier has a current sound, and some models will also have the situation that the bigger the accelerator, the louder the current sound, this product can solve this problem. 5. If there is current sound between the power amplifier and the speaker or the speaker, this product can be installed between the power amplifier and the speaker. 6. If the laptop is connected to the projector and the power amplifier at the same time, there will be noise. You can connect the laptop to the power adapter or use the battery. At this time, the noise disappears when the power amplifier is unplugged, or the same noise disappears when the projector is unplugged. Then you can connect the headphone jack of the computer and the power amplifier A common ground isolator is added in between to eliminate noise. Unable to eliminate noise problems: 1. The noise caused by the non-common ground cannot be filtered by this model, such as electromagnetic interference. Be sure to confirm the source of the noise before purchasing. 2. Because everyone has different expectations for the isolation effect and different senses, some customers feel good and some customers feel bad. This product is an audio common ground isolator, which is effective for the noise caused by the common ground of the audio source and the receiving equipment. To put it simply, the common ground means that the grounding points of the two electrical appliances are not at the same point. Due to the difference in grounding resistance, noise is transmitted into the electrical equipment through the ground wire, causing interference. Because the grounding points of the two devices are different, it is possible to generate common ground noise. In the car audio, there is a kind of audio interference, like a humming sound similar to a whistle, and the frequency of this noise will change with the speed of the engine. Therefore, this product can only eliminate noise and current noise caused by common power and common ground products, but cannot eliminate noise caused by other reasons, so you need to confirm the source of the noise yourself. Note: Due to the different monitor and light effect, the actual color of the item might be slightly different from the color showed on the pictures. Thank you! Please allow 1-2cm measuring deviation due to manual measurement. Packages: 1/2 x Noise Isolator