I bought this battery of Bundle Star because in my opinion the Sony battery pack is too expensive. A few concerns I had if this would work on my new Sony Alpha 57. In this regard, my expectations were exceeded, however. It fits like the original wonderfully into the case, the state of charge is displayed properly in the camera and I can take as many pictures with it. Of course, it fits into the original charger. This battery has a perfect price-performance ratio.