Humidity is removed from the cabinets by use of a powerful desiccant. Moisture absorbed by the desiccant is vaporized and released outside the dry box. Digital controls record the temperature and humidity over time. Nitrogen cabinets are a more expensive way to purge moisture. They use a constant positive pressure flow to void the cabinet of all oxygen, which forces out all moisture and contamination. Dry cabinets have automated control systems that allow electronic manufacturers to manage and track their MSD devices. They use automatic data collection technology, such as bar coding and radio frequency identification. The automated systems eliminate the need for manual procedures, such as identifying MSDs, filling out log sheets and entering time calculations, which are time-consuming and open to human error.