CMEXpert ll Concrete Moisture Meter performs direct-contact concrete surface moisture testing to ASTM F2659 and can measure up to 6.9% moisture content. This meter can be used with Hygro-i Relative Humidity Probes (sold seperately, inquire) with an electronic interface cable for ambient measurements of relative humidity, temperature and dew point. The cable is also included with the HM-85 kit. The unit’s relative humidity range is 0—100% non-condensing. Humidity accuracy of between 10%—90% is ±1.8% at 25°C (77°F) and ±3% above 90%.