G1 3.5mm Audio Noise Reduction Isolator Bluetooth Receiver 1. Hum elimination: eliminates hum noise caused by ground loops when the audio source and (some car speakershome audio systems) use the same power supply, resulting in clear music enjoyment, and the excitement blooms from there 2. Pure sound quality: no damage of rock music, give you a better experience, can be used on mono 3. Easy to use, just plug and play, no battery required 4. Small and portable, this gadget does not take up much space and is easy to take away Unable to eliminate noise problems: Noise caused by non-common ground cannot be filtered by this model, such as electromagnetic interference, etc. Be sure to confirm the source of the noise before purchasing Because everyone has different expectations for the isolation effect and has different senses, some customers think it is good, and some customers think it is not good 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 device 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, the noise is transmitted into the electrical equipment through the ground wire, forming interference. Because the grounding points of the two devices are different, common ground noise may be generated. It is manifested in the car audio, that is, there is a kind of audio interference, a humming sound similar to whistling. The frequency of this noise will change with the engine speed. Therefore, this product can only eliminate noise and current noise caused by products with common electricity and common ground, but cannot eliminate noise caused by other reasons, so you need to confirm the source of the noise yourself Determine whether the noise is caused by a common ground: 1. Use earphones to connect to the AUX (3.5mm interface) of the car MP3 and car navigation.