Any have some info to share, greatly appreciated
I believe that the Ultima brand is a Rayovac battery, private labeled by Starkey.
Maybe ZCT can confirm this.
Rayovac batteries in general are very good. Just a little pricier than some imports, such as I Cell Tech Hearing Aid Batteries.
That’s what I was thinking too. I’m pretty sure that Ultima is a private label brand for Starkey, made by Rayovac.
Starkey have two versions, the standard, and the gold. The latter has a 24K gold plate on the negative terminal, which is supposed to help with conduction. These premium batteries last 10% longer than the standard.
In general, Rayovac seem to make some very good hearing aid batteries. They are full guaranteed against leakage or failure.
The top-end Rayovac batteries in the UK are stainless plated which rumours suggest increases their size and thus may prevent good air flow in the Phonak & Unitron micro BTEs possibly causing power supply problems.
Now whether these rumours are valid or not, I don’t know.