Fossil fs4141 battery size - Fossil Watches

Fossil battery replacement sizes are usually a 2430 (CR2430), 371 (SR920SW), or 377 (SR626SW).
https://www.fossil.com/en-us/******/how-to-change-a-watch-battery

Fossil Watch Battery Replacement - Ultimate Size Guide -

batterymole.com https://batterymole.com > fossil-watch-battery-replace...
Aug 21, 2022 - The CR2430 battery is a 3v lithium battery, see the shape below. This example is made by Renata, but you can also get the produced by Duracell, ...

Take it to a watch specialist who will open the case and be able to measure the battery compartments dimensions to specify the required battery and replace it for you.

Thanks for contacting Fossil.
The only way to know the battery size is to pull out the old one. It might also be in your manual. It might be on the outside of the watch.
If battery is missing, then you will have to measure the cavity and match it against a battery chart.
Best wishes.

to change the battery of fossil blue watch,just open the case back and remove the old battery,look the number size on the battery and put a new battery that same number size ,after replacing battery press the case back tight to avoid water damage !good luck