The Delmhorst RH/T-S2 Sensor measures the Relative Humidity in concrete following the ASTM F2170-11 standards. If you want the sensor that measures everything else its the Delmhorst RH/T-S1 Sensor. The sensor is designed for the Delmhorst TotalCheck, HT-4000 and Navigator Pro. The sensors also come in packages of 5.