Anyone know what size battery this seiko takes? I can't find anything online and I don't want to send it out for a repairman to charge me if I can do it myself ..the numbers on the case back read 6923-7039-A4

 

https://www.google.com.au/search?q=...ved=0ahUKEwjzrqSHvMfLAhXCCY4KHdsnAIYQ_AUIBigB

 

Measure the diameter of the battery enclosure in mm and then see if you can get the depth. Then use the charts that @STANDY pointed you to to find suitable batteries.

At a guess, an SR926SW.

BUT!

Before you put a new battery in that watch, you need to address the corrosion issue, obvious result of a battery that has leaked in the past.

 

And I'm amazed that you couldn't find anything on-line. Are you sure you were connected to the internet?

 

SR926SW didn't fit right was little too thick; where do you see corrosion though?

 

SR926SW is correct, from the caliber parts list:



If you can't get an SR926SW in then try an SR927SW (9.5mm x 2.73mm), if that's too thick, go down to an SR920SW (9.5mm x 2.05mm).

Corrosion is here