The DEWALT 3/8 in. Filter Regulator with Lubricator is used to filter out contaminants, regulate your air lines and lubricant your air tools.The filter regulator with lubricator ensures your tools receive the proper airflow and the filter ensures your air is clean with a lubricator to oil your tools properly. This regulator/lubricator also comes with a flow sensor design that provides nearly constant oil/air ratio over a wide range of air flows.