The Model 3900 Low Humidity Generator is an extremely accurate means of producing known humidity values for calibrating and verifying humidity instrumentation. Based on the combined, NIST proven, fundamental “two-pressure” and “two-temperature” principles, this system will automatically supply a continuous humidified gas stream, within the frost/dew point range of –95.0 °C to 10.0 °C, for days or even weeks unattended. Simply apply power to the system, and the 3900 will power-up ready to purge and/or generate. Humidity setpoint values are input by the operator from the front panel keypad and are limited only by the operational range of the 3900 humidity Generator.