PCE-WB 20SD is a multifunction wet bulb temperature data logger used to measure indoor / outdoor wet bulb globe temperature (WBGT), black globe temperature (TG), wet bulb temperature (WB), dew point temperature, air temperature (TA) and relative humidity. Thus, this multipurpose data-recording device is an ideal tool for evaluating heat stress risks in different work environments. The device is also used by indoor air quality (IAQ) inspection professionals to assess the performance of heating, ventilation and air conditioning (HVAC) systems.