I bought this particular battery as a back up for my Panasonic Lumix DMC-S1 camera (DMW-BCK7E battery) at a reasonable price; substancially less than an Original Brand price. I had a good look around Amazon first and found quite a few 'suitable alternatives' - some cheaper than the Ex-Pro - but, the nearest in spec' I could find was this one (3.7v 680mAh -Vs-Panasonic 3.6v 660mAh 2.4Wh). Being technically ignorant I thought I'd 'play fairly safe' with the Ex-Pro and haven't regretted it. It works perfectly well and I can't tell its' performance from the supplied Original. It also has a 2 Year Warranty, which I hope not to need! However, it is recommended to fully discharge before fully re-charging; presumably to avoid battery 'short term memory' problems.