Portable metrology drywell units quickly and accurately calibrate bimetal thermometers, temperature sensors including RTDs and thermocouples, and temperature switches in the field. Their drywell technology creates specific heat zones that provide even and stable temperature distribution. Features like the large LCD display, function keys, and menu options allow easy operation and programming. The front panel has outlets for plugging in other instruments, and with built-in process electronics, users do not have to bring multiple tools to the field. They are commonly used for transmitter loop calibrations, comparison calibrations, or for checking and calibrating thermocouple sensors.