It was to replace the battery of an old mac (6 years) which I use in troubleshooting and did not want to invest too much. Look side, it is not at all the same type as that of aluminum MacBook and the battery exceeds slightly, but it is underneath and it's not too serious. Performance rating, I have not yet had the opportunity to make many discharge / recharge cycles, but for now everything is fine. The analysis with coconut battery announcement: Design capacity 5200mAh Current capacity 5377mAh 5377mAh Maximum load