Wrench to unscrew the back of SEIKO watches. I'm not sure how standard this back cover is. I assume it will work with other watches. As always, I have included the OpenSCAD code, so you can adjust if it doesn't fit with your watch.

I'm sure there are plenty of other model for it. It was easier to make my own then looking for one that fits the specs for my watch.

It's very simple. Quick print. It works very well, even when printed with PLA.

Feel free to redistribute your own version.