The International Organization of Legal Metrology (OIML) is a worldwide, intergovernmental organization whose primary aim is to harmonize the regulations and metrological controls applied by the national metrological services, or related organizations, of its Member States. The two main categories of OIML publications are: • International Recommendations (OIML R), which are model regulations that establish the metrological characteristics required of certain measuring instruments and which specify methods and equipment for checking their conformity; the OIML Member States shall implement these Recommendations to the greatest possible extent; • International Documents (OIML D), which are informative in nature and intended to improve the work of the metrology services. OIML Draft Recommendations and Documents are developed by technical committees or subcommittees which are formed by Member States. Certain international and regional institutions also participate on a consultation basis.