Large-caliber current clamp design for measuring any grounding resistance of complex grounding conditions such as single point and mesh grounding; Precision 4-wire method, 3-wire method and simple 2-line method, selection method, double-clamp method measurement; Fast filtering technology, with excellent anti-interference ability and environmental adaptability, repeat test consistency, ensuring measurement accuracy, stability and reliability. Data storage function for 500 sets of data storage; Upload to PC via USB data cable for display analysis and output test report