My "old" batteries held 1-2 weeks and were also of size 312 Rayovac.
The "new" Rayovac Extra Advanced keep me good 2-3 weeks, presumably with
named "Extra Advanced" related.
Conclusion:
For hearing aid users who have not purchased their size 312 batteries audiologist for a lot of money, this is a cheap and good alternative.
I'll buy most likely again this set and forgiving due to the price / Leistungsverhältns 5 Stars.