This BB-4A is a blackbody temperature reference source which is adjustable over the range from 100 to 982°C (212 to 1800°F) and accurate to ±1°C, ±0.25% rdg. It has a built-in digital temperature controller to provide accurate, stable temperatures as well as to provide the temperature readings of the cavity. The heated cavity provides a target of known temperature and emissivity, and virtually any infrared pyrometer with a spot size diameter less than 22 mm (0.88") can be calibrated. The compact, portable design allows for quick and easy calibration setups. Both models come standard with an RS232 computer interface which allows computer control of the setpoints for automatic test applications. A NIST traceable calibration certificate is also provided.