1. Large-diameter current clamp design can measure any grounding resistance value in complex grounding conditions such as single-point and mesh grounding; 2. Precise 4-wire method, 3-wire method and simple 2-wire method, selection method, double clamp method measurement; 3. Fast filtering technology, with excellent anti-interference ability and environmental adaptability, strong consistency of repeated tests, to ensure the accuracy, stability and reliability of the measurement. 4. Data storage function, can store 500 groups of data; 5. Upload to PC through USB data cable for display analysis and output test report