Historically, ampere-hours and milliampere-hours (1Ah = 1,000mAh) have been the popular units for rechargeable ... the battery's voltage. This is why two batteries can have identical mAh ratings ...

Keeppower USB Rechargeable AA Batteries offer a comparatively higher capacity of 2260 mAh per cell. The item has a 4.6-star rating on Amazon, which is one of the highest in its category ...