S480 4 Terminal Earth Tester is a robust and compact automatic earth (ground) test instrument designed to measure earth electrode resistance and soil resistivity. It has several test modes but excels at the 4 terminal method, which eliminates both the contact resistance and the wire resistance. The instrument is also installed with the Fast Fourier Transform and Automatic Frequency Control technology, making it high in anti-interference capability. These technologies alongside the 4 terminal method, results produce is of the highest accuracy. Soil resistivity measurements are often used for establishing the optimal electrode design and site for a grounding system, or it is also often used in geological or archaeological investigations.