Buyers should focus on the Geophysical Method employed by the device. The most common technologies include Natural Electric Field Frequency Selection (ADMT), which is portable and efficient for deep exploration, and Electrical Resistivity Tomography (ERT), which provides high-resolution 2D/3D imaging. For professional geological surveys, ensure the device features Automatic Mapping capabilities to visualize aquifers in real-time and High-Precision Sensors with a resolution of at least 0.001mV to detect subtle geological changes.