Handheld WBGT heat stress monitor with a black globe sensor and humidity/temperature probe that together compute Wet Bulb Globe Temperature alongside heat index, dew point and barometric pressure. A multi-line backlit LCD shows several readings at once, with a user-settable audible alarm and onboard memory for up to 99 readings, aimed at OSHA-style workplace heat-exposure checks. This NIST option supplies the same R6200 unit with an added traceable calibration certificate.