Hasselblad metered finder battery requirement

I have a ca 1980 Hasselblad metered finder. It has no model style of any kind on it. My research seems to have it being model PME51. I've inquired on another photo talk site, but seem to favor the credibility on this one. Anyway, my research shows this finder to take a PX28. But that's in 1980. Now, the 544 seems to be the cross-reference for that. But these days 544 is alkaline, which has a perfectly awful voltage discharge curve. So I suppose my question is 2-part. 1) Was the original PX28 a mercury battery in 1980?, and 2) Does the finder have a built in voltage regulator set to say... 4 volts or so, so that a bad discharge curve becomes a moot point? Thank you.

The PX28 is/was a silver-oxide battery. The alkaline versions are inferior for use in most photographic uses, because of the discharge curve.

Here is one on Amazon right now: http://www.amazon.com/Kodak-PX28-Battery-volt-Silver/dp/B00009R6T2

They are apparently still used in great numbers in dog collars. Here is another link: http://24hourbatteries.com/shop/px28battery__340.html

I buy them in quantity over the internet, because I have Mamiya cameras/accessories that use them. They were also used in Canon AE1's and A1's (among others).

Thanks Mattking. I'll go with that. Silver is better than alkaline on the voltage discharge curve. I'd still be curious to know if Hass built a voltage regulator into the circuit, just for the sake of curiosity. A silver is better than an alkaline, but a mercury was better than them all.


Edited. Come to think of it this may be a dumb post. It occurred to me that if the original was mercury, it would have been only 5.4 volts. Wait--5.4 volts would fit in with it being named a 544 battery. I wonder what the 544 was in 1980. Now I'm going nuts. Any Hasselblad reps on here?

I suppose myquest to get to the bottom of the truth on these batteries is my ownership of a Pentax ES, which took a 544. But in 1971 when the ES was introduced, the 544 was the correct battery. It just seems odd that the 4 button cells inside the 544 case were undoubtedly mercury (or could I be wrong?) And I thought it odd that 4 X 1.35 volts = 5.4. And they called it a 544 battery.
I'm happy with Matt's assessment of the Hasselblad finder taking the silver 6V, but I still wonder what the original 544 was. Go to Radio Shack or anywhere 544's are sold, and they're all alkaline. I wonder if the original 544 was actually mercury.

At the bottom of this page
http://www.photoethnography.com/ClassicCameras/HasselbladFinders.html
Either silver oxide or lithium
the Pentax manual says 6 volt silver (544)
http://www.cameramanuals.org/pentax_pdf/pentax_es-1.pdf

Alright! Thanks. I can put that little brainstorm to bed.