The International Organization for Standardization (ISO) is a worldwide federation of national standards bodies, at present comprising some 130 members, one in each country. The object of ISO is to promote the development of standardization and related activities in the world with a view to facilitating international exchange of goods and services, and to developing co-operation in the sphere of intellectual, scientific, technological and economic activity. The results of ISO technical work are published as International Standards. Among these International Standards are standards which are developed for metals and their alloys, including their designations. The letters ISO alone indicate the document is a standard, ISO/R or ISO R indicates a recommendation, and ISO/TR represents a technical report. Example: ISO 2938; ISO R683-6; ISO 683-18