1. The operation is very simple: easy to use, just plug and play, no battery required. Compact and portable, this noise isolator does not take up too much space and is easy to remove. 2. Clear music enjoyment: buzzing caused by grounding circuits when using the same power source as some car speakers/home audio systems, achieving clear music enjoyment. 3. Compatible models: Suitable for any portable device with a 3.5mm audio jack when grounding issues persist, used for car audio systems and home stereos. 4. Ground Circuit Noise Isolator: This product is an audio common ground isolator that is effective in reducing noise caused by the common ground between the audio source and receiving equipment. Colour:Black Material:plastic Package Contents: 1 x audio noise 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.