Ziyou Zou 5 Battery reported just over 69000 mAh on a full charge in Windows' battery report. After a few week's use, the battery has been remarkable. For office tasks (Excel, web data searches, etc) the battery easily lasted over 10 hours for me, and my screen brightness was kept very high.The battery casing appears to be genuine Panasonic. The cells inside could be aftermarket but the battery part number inside the battery report matches the Panasonic specifications.