The HT30 is a Heat Stress WBGT Meter designed to measure Wet Bulb Globe Temperature, which considers the combined effects of temperature, humidity, and direct or radiant sunlight on thermal stress. The meter features measurement of Black Globe Temperature (TG) to monitor solar radiation effects, Air Temperature (TA), and Relative Humidity (RH), with selectable display units in °F and °C. It includes an In/Out function to display WBGT values with or without direct sun exposure, a built-in RS-232 interface for data connectivity, and operates on two AAA batteries with auto power-off capability. The HT30 is ideal for athletic training, monitoring outdoor working conditions, and manufacturing environments where heat stress assessment is critical for worker safety and performance evaluation.