Replacement LiPoly notebook battery for APPLE MacBook Air 11 inch 4 Cells MC505LL/A MC506LL/A MC507LL/A Replaces A1375 661-5736 020-6920-01 020-6920-A 020-6920-B 020-6921-B Specs 7.3V 5200mAh 38Wh Warranty: 18 months from date of purchase