Hearing aid batteries are tiny, and the hearing aids themselves small and difficult to work with. The batteries have to be changed frequently, which used to be a truly difficult task. Moreover, the batteries would often run out in inconvenient locations (dark, crowded places), and people who have hearing aids tend to be elderly, with restricted vision and sometimes poor hand coordination. I think Everyready first noticed the problem and came out with a clever holder for the batteries that extended an arm that held the battery, allowing for much simpler insertion. Duracell soon followed with a simpler mechanism that in my limited tests, is somewhat superior. But kudos to both companies: a real aid -- and not just for the elderly: it simplifies the job for everyone.