This BB-4A is a blackbody temperature reference source which is adjustable over a range of 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 22mm (0.88") can be calibrated. The compact, portable design allows for quick and easy calibration setups. Both models come standard with an RS-232 computer interface which allows computer control of the setpoints for automatic test applications. A NIST traceable calibration certificate is also provided.