The Edgetech Instruments Model DewTrak II dewpoint/humidity transmitter is an optical chill mirror hygrometer designed to continuously measure the moisture content in gases. The instrument is powered by 24Vdc.

The DewTrak II uses the chilled mirror dewpoint temperature condensation principle to determine the water vapor concentration in gas mixtures, and a platinum resistance thermometer to accurately measure that temperature. Outputs include 4 to 20mA, 0 to 5 Vdc, or 0-10Vdc and an RS232 serial port as well as electrically isolated relay contacts.