What number of the battery model a15542

Unfortunately, the Seiko website does not have a serial number lookup, so you'll have to identify the model. The "8123-7190" is what Seiko calls the "caliber code." Entering that on the page linked below will narrow down the model number list for you. Clicking on the link for your model will give you the instructions in PDF format. The instructions for your model tell you what size battery to use. For example, the manual for the 8F32 states on page 11 that the battery size for that model is CR2412. (Note - be sure to get the correct instructions; different models have different battery sizes.) "Automatic" Divers watches have no battery, they are powered by a spring mechanism.

If you look at the movement inside the watch it should be possible to find the movement number (you might need a loupe or magnifying glass to see it clearly) and name (e,g, Seiko-Epson, Miyota etc.)
If you can supply that information I can tell you which battery it requires.

if it needs a new battery you will be better off taking it with you to a shop that sells watch battery's as 90% of the time they will fit it for free too ( and if they open it to see which battery it needs and they dont have one then get the model number while its apart )

That's the battery number for the watch also known as the #377. It's the most common watch battery in the world. Your model number is located at the bottom of the dial (face) below the six-o'clock position. You will need a 10 power jeweler's loupe or magnifying glass to see it and read it. Jot down the number and contact Elgin directly (MZ Berger Co,) for the extra links.
MZ Berger.

You should beable to pop the back off to see battery number or places like wally world etc.. will replace the battery for just the cost of the new one no labor

Hi there, can you look on the back of the watch for the model number. It should be similar to 7T62-0AC0 - I can then tell you which battery you require -

Give us : make, model and all the writings on caseback. Photo will make it easy as well.

the size cell that goes in this watch is a 395...good luck :)

Yes, your watch definetely needs a new battery. Find your nearest watch repair shop and ask to replace battery. Your watch will tick as brand new.:))