About the only sure method I have found to determine what is counterfeit and what is real, other than by very close examination of the 'fit and finish' is the weight.

Real batteries are typically significantly heavier than the fakes, even discernible between two AAA types. And if you have a 4, 6 or 10 pack to compare, it is even more obvious.

You would also find out when you send that damaged piece of equipment back to Duracell or Eveready and have them inform you whether the batteries are real or not.

Peter Wieck
Melrose Park, PA