The AEMC Digital Ground Resistance Tester Model 6471 (2135.49) is a portable measurement instrument designed to measure Ground Resistance with 2 clamps , no auxiliary rods, Bond/Connection Resistance (2-Pole and 4-Pole Kelvin sensing), Ground Resistance (3-Pole or 4-Pole), Ground Coupling Resistance, and Selective Ground Resistance, Soil Resistivity (Wenner or Schlumberger method). The 6471 measures from 0.01 to 99.99kΩ and is auto-ranging, automatically seeking out the optimum measurement range, test frequency and test current.