System "1 copy 2.1" consists of 1 single label with the appropriate program, when applied to the subject in 2 days made on it BJ the correct version, and the sticker can be left or safely throw away (it worked out).
The subject of the later charge is not lost, as in the industrial source exchange for another item is not possible. Benefits - cheaper, decide charge form factor. For us, the system manufacturer "1 copy" is much simpler fabrication of the system transfer for You, if you do not change the primary carrier (e.g. a clock) is easy, cheap and convenient.