OEM batteries are batteries made by the Original Equipment Manufacturer, that is to say, the same manufacturer that Apple sources to build their batteries. Whereas the Aftermarket batteries are made and sold by third parties not affiliated with Apple in any way.

The batteries created by third-party manufacturers vary in terms of quality. We source our aftermarket batteries from reputable manufacturers that offer us a 1-year warranty on the battery. In terms of performance, the aftermarket batteries will have slightly less charge capacity than the OEM batteries but it might not be obvious to the everyday user.