The AEMC 6471 Ground Resistance Meter measures Connection/Bond resistance (2-Pole and 4-Pole Kelvin sensing), Ground Resistance with 2 clamps (no auxiliary rods, 3-Pole or 4-Pole), Soil Resistivity (Schlumberger or Wenner method), Selective Ground Resistance, and Ground Coupling Resistance. Measures from 0.01? to 99,000? with an auto-ranging feature to seek out the ideal measurement range test frequency and test current.