Review on 8000+MAh A1466 Battery Replacement For MacBook Air 13 Inch (Mid 2012-2015, 2017) And A1369(Late 2010, Mid 2011) by Matthew Henderson

Bought 8000 MAh batteries and that seems to be true. Supposedly they are the 4.0 version with new and improved duration, safety,etc. Actually, they are manufactured in 2015 as shown in the included pic (checked with many apps) and reported in other buyers comments. I did the callibration but from the first first cycle till the fourth the battery life when fully charged does not exceed 4 hours, less than half of the original Apple battery when new. The manufacturer still claims they are new but several emails back and forth offered to send a replacement as I requested. Will wait and see if their promise becomes true.Update: I was sent a replacement and did the calibration religiously according to the included instructions and video. If I only have one browser and no other program running, with volume and brightness turned down, no blue tooth, etc I was able to get close to 7 hours in the best occasions