I just looked up the part number on my "puffed up" K2 battery. What is interesting is that I found an
equivalent battery with the same part number, but that says "Sony" on it (like in the first photo in this thread that has a different part number). Strangely, this K2 LiPo battery lacks "Sony" on it -- is amazon using cheaper Sony knock-offs? Or are they just "multi-sourced" based on supply and demand?
Same part number as on K2 LiPo, but with "Sony" label (missing from K2 LiPo).
Both batteries have that "backwards UR" logo on them (K2 and PW), but the K2 is missing the "Sony" label. See photos in previous posts...