The can be used to calculate the prevailing dew point temperature quickly, easily, and economically in combination with a dew point calculation table. Accurate dew point temperature information is important to ensure that the substrate temperature remains above the prevailing dew point thus avoiding condensation on the substrate. Rapid rotation of the results in air movement around the thermometer bulbs, one of which measures the ambient temperature, the other measures the wet bulb (being housed in a reservoir in a fabric sleeve). The resulting temperature readings can be used with the dew point calculation table or dew point calculator to show the dew point. The is supplied in a hard plastic protective case. Complies with International Standards: BS 2842, ASTM E 337 B.