The written document defining the quality, performance, and installation standards for materials and systems - the counterpart to the drawings' "what" and "where.". If drawings show what goes where, the specification says how good it has to be - which standard a material must meet, how it should be installed, and how it's tested or certified. On BIM projects, specification sections (often organized via MasterFormat or a national equivalent like NRM) are increasingly linked directly to model elements rather than living in a completely separate document.