If you are unable to detect metal, it may be caused by the following conditions: 1. The battery may be low, please replace it with a 9V battery and try again. 2. The distance may be too far, and the detection distance is proportional to the surface area of the metal. 3. Maybe the metal detector cannot sense the change of magnetic field (its working principle is to detect metal by detecting the change of magnetic field). Therefore, when searching for metal, please slowly approach the metal.