SR44 (or S76, EPX76, PX76, MS76, V76PX, 357) is silver oxide,
LR44 (or A76) is alkaline, the latter's cheaper and shorter lived.
544 (or V28PX, 28PX, 4SR44) is 4 cell (6V) silver oxide,
A544 (4LR44) is 4 cell (6V) alkaline.
Check Eveready, Duracell, Varta, or one of the other battery manufacturer's
web pages or check www.mouser.com or www.digikey.com or other electronics
supplier under photo cells or button cells.

"Richard J Kinch" wrote in message
. ..
Jim K writes:

I just bought an Energizer 357/303 for mine. It's replacing the SR44

A genuine 357 is exactly the same silver oxide cell as SR44, just a
different name.

Beware that Radio Shack sells a 357A which is alkaline, and that a lot of
the cheap Chinese cards of button cells claiming to be 357s or "replaces
SR44" are also just alkaline. You can buy Chinese button cells cheap on
eBay, but the sellers typically have no clue about alkaline vs
silver-oxide
non-interchangeability. Don't believe claims that alkaline cells are
replacements for silver oxide, or that LR44 is just a cross-referenced
equivalent to SR44 or 357.