The Concrete Encounter CMEXpert is a digital display version of the Tramex Concrete Encounter CME4 hand-held electronic impedance moisture meter. It operates on the principle of non-destructive impedance measurement. Parallel co-planar electrodes are mounted on the base which, during operation, transmit low-frequency signals into the concrete floor. To carry out moisture tests simply brush any dust from a smooth area of concrete and also from electrodes, switch on the CMEX, hold to the surface to read the percentage moisture content. There’s absolutely no surface damage and no waiting. Flooring Manufacturers Recommended.