This battery is the original in every way and I can only confirm that this battery lasts longer than that of Nokia.
The installation is not particularly difficult for clever tinkerer since declared enough video footage on Youtube this process step by step!
Therefore, like 5 star and my absolute buy recommendation!
Update 6/12/2014:
After two weeks use, the battery will discharge faster than I can look and is also totally hot! The thing does not hold a half day more and I now again an original Nokia battery in it, so far without any problems.
Can it therefore be advise against this battery to buy, dear to the original product only rely strongly.
It would be interesting just to know what happened to the other reviewers so ...