MediaWiki:Wikibase-listdatatypes-quantity-body/en

Literal data field for a quantity that relates to some kind of well-defined unit. The actual unit goes in the data values that is entered.
 * amount – implicit part of the string (mapping of unit prefix is unclear)
 * unit – implicit part of the string that defaults to "1" (mapping to standardizing body is unclear)
 * upperbound - quantity's upper bound
 * lowerbound - quantity's lower bound