The battery itself, I am reasonably happy. The performance and life is ok but not great. But unfortunately the installation could be done a few days later, since the tool was not sufficient. On IPhone 4 2 different screws are installed, on the one hand and the Phillips screws Pentalope. So I could indeed open the iPhone without problems, but the battery is not exchanged.
With a new tool I could then later change the battery.
Now again briefly on battery power. I have just installed the battery without checking or similar something. The battery lasts in normal use approximately one half to a full day longer, as my 3 year old battery. Although this is significantly longer, but compared to a new not really good.
The price is ok and I had no problems with the general function, I forgive 3 stars.