This was a waste of money! Used for my mother's hearing aid batteries, when I'd test one to see what the battery life was before putting back in the hearing aid, the tester would show 100% then a few minutes later her hearing aid would signal the battery was dying. I'd actually take it out, try it on the battery tester several times and it would still show 100%. We'd go through the process of inserting it, taking it out and testing it a couple of times before the tester would show it at 80% I haSee full review