This device can work efficiently on wooden walls, windows, steel plates, doors, cement walls and concrete walls which are up to 10 inches thick. It comes with earphones and has a volume dial to amplify sounds that you want to hear. The Spy Wall Listening device is highly sensitive and you need to carefully adjust its audio such that is does not cause any kind of discomfort to your ear drum.
|• Jack: 3.5mm||• ON/Off Switch Button: Yes|
|• Dimension: L:43 x Diameter:36 (mm)||• Battery: Built-In rechargeable battery|