After the original battery no longer provided the desired performance, I went in search for a replacement, with this product for the Nokia 5800, I thought to have found. When the article arrived, I treated the new battery properly with charge and discharge. After about 4-5 times this also yielded the desired duration. However, within a short time, after about 3-4 weeks the situation changed seriously and the performance did not reach the desired height, on the contrary, the battery built more and more now and finally had a lower duration than the original battery which I had fortunately still.
After a brief consultation with the seller of this assured me a refund when returning to the battery. The battery was properly in padded envelope back to the seller - money? I have until today none seen. Luckily it was only 5.95 - a mess is yet!