Works on wooden walls, doors, windows, steel plates, etc.Highly Sensitive, carefully adjust audio slowly, as not to cause discomfort to your ear-budsThis audio gadget works by amplifying the vibrations of audio. When people are talking in a room their voices are simply a waveband, and depending on how loud they are talking, the waveband travels short and long distances which are picked up and amplified by this device.colour:Black + SilverMaterial:metalPackage Contents:1* Detecotor1* USB Cable1* Circular probe1* Needle probe1* Headphone1 * use ManualOnly the above package content, other products are not included.Note: Light shooting 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. When shopping, please pay attention to the size and dimensions of the product to ensure that it meets your needs. In the title and , we have provided detailed information about the product, including its features and specifications We want you to be completely satisfied with your purchase, so if you have any questions or concerns, please dont hesitate to contact us. We are here to help and will do our best to assist you. Thank you for choosing our product. We hope you enjoy it Note: Due to the light and screen setting difference, the item's color may be slightly different from the pictures. Please allow slight dimension difference due to different manual measurement. Sold by-DIMEANI official store