Bought for my a57 2 pieces of these batteries. Unfortunately I can not confirm the positive reviews. The performance is weak. After several charge cycles I manage with a maximum of 110-120, the other about 140 images (without films). The batteries are worth as much as its price: Ca. 1/4 of the original batteries and thus only as "emergency reserve" when traveling useful. PS: I'm going to even try to continue working for the empty display, to actually goes nothing. Maybe that's right not display.
Nacxhtrag 09.08.2012: I have returned the two batteries and appointed two new. These now provide about 300-350 photos. I am satisfied with and have my rating raised to 4 stars.