Polarity is reversed
I replace the battery in a bluetooth speaker.  As one of the other reviewers noted, the polarity of the plug is reversed.  As long as you are aware of this and make the proper adjustments, you will be fine.  The battery itself charged without any issues and hold a charge very well.  If it wasn't for the polarity issue, I would give it 5 stars, but  because this could cause catastrophic damage to electronics if not noticed, I had to take a couple of stars off.  I wouldn't have checked the polarity if it wasn't for the other reviewers comment and could have damaged my speakers.
Rating: 3 stars