The Concrete Encounter CME4 is a hand-held electronic moisture meter operating on the principle of non-destructive impedance measurement. Parallel co-planar electrodes are mounted on the base which, during operation, transmit a low-frequency signal into the concrete floor to a depth of approx. 12.5mm (0.5 inch).
While concrete under normal conditions can never be completely dry, the instrument has been calibrated on acceptably dry material. In operation it compares the change in impedance caused by the presence of dampness and displays this on a clear, easy to read analogue dial.