Digital psychrometers, also known as digital humidity meters or thermohygrometers, measure ambient temperature and humidity. The primary integral probe is either onboard or cabled for easy access in tight places. Select psychrometers have additional measurement or calculated measurement features like Wet Bulb Globe Temperature (WBGT), dew point, or heat index. Users in demanding inspection roles may need a psychrometer with a long-form calibration certificate to ensure the model has been tested to meet standards of accuracy. Meters with data-logging capability provide ongoing readings at regular intervals and store data for tracking and validation.