A length of time. Duration values are in the ISO 8601 duration format, where P represents 'Period', nY represents the number of years, nM the number of months, nD the number of days, T is the date/time separator, nH the number of hours, nM the number of minutes, nS the number of seconds. So P2DT23H32M51S means 'A period of 2 days, 23 hours, 32 minutes, and 51 seconds'. PnYnMnDTnH nMnS (e.g., P2DT23H32M51S) We use the duration data type to convey values like the time left until a listing ends. For ended listings, the time left is PT0S (zero seconds). xs:duration is part of the XML schema namespace defined as: xmlns:xs='http://www.w3.org/2001/XMLSchema'