So that otherwise identical units can be shipped with unique keys.
There was an identical unit on the floor above.
You have two very similar units, almost identical units at the same site.
Serial numbers identify otherwise identical individual units with many, obvious uses.
A planned second identical unit was cancelled soon after construction began following a change of government in 1983.
His next-door neighbor paid $90,000 for an identical unit some years earlier.
The plant's two identical units went into initial operation in 1971.
The plant consists of two nearly identical units, launched into operation in 1974 and 1975.
From his study, he knew that there was an identical unit on the other end of the compound's semicircle.
He didn't want to take someone else's spot, though he wasn't sure how anyone could find a certain cell among these identical units.