Casio AQ-321G Battery

[Waggy]

Hi all, needing a little help. I have an old Casio AQ-321G, but have no idea what battery it takes. I've looked around online, but cannot see anything... I see a 309 stamped on the case back, could this be it....?

Can you please help, below are some pictures:

[HectorLooi]

I think it's stamped on the inside cover. 309 I think.

[watchweasol]

Hi. Thing to do is measure the battery space.  Diameter.  X depth ..    I have seen it listed as  sr626sw.  377 measure to check then check the dimensions of the 377.    

[Senyamnesi]

I swapped mine with a 377 and it's worked fine for over a year. Just make sure the contact springs are clean and sitting right when putting it back together.

[Senyamnesi]

1 hour ago, Senyamnesi said:

I swapped mine with a 377 and it's worked fine for over a year. Just make sure the contact springs are clean and sitting right when putting it back together.

I had to deal with the same battery confusion on my old Casio. For the AQ-321G, I used a lr41 battery equivalent and it worked fine—no issues with fit or powering the module. Just make sure the contacts are clean and you haven’t lost that tiny spring during the swap, which almost happened to me.