A UNS designation is not a specification because it establishes no requirements for delivery conditions such as mechanical property requirements, heat analysis tolerances, heat treatment, packaging, marking, inspection, etc. UNS designations are identifying numbers for metal and alloys for which controlling requirements are established and published by technical societies and specifying organizations such as ASTM, ASME, and AWS. There are almost 5,000 UNS designations for metals and alloys. The UNS listing includes cross-reference specifications for many technical societies and specifying organizations, but it was not meant to be an exhaustive list. The list includes representative specifications from American Society of Mechanical Engineers (ASME), American Society of Testing and Materials (ASTM), SAE, NACE, Federal, Military, American Iron and Steel Institute (AISI), and American Welding Society (AWS). Metals & Alloys in the Unified Numbering System is a joint publication of SAE International and ASTM.