I used some of these years ago. On the plus side, I think they are better than accordion bottles, however, not that easy to clean or load. Still, you don't do that all that often.

I now have changes to storing developer in a bunch of small amber glass bottles, filled to the brim, and used one shot. Easy to fill, easy to rinse after use, and easy to tell how much you still have.

Funny, started with glass, then evolved to plastic that could be squeezed to limit air,then accordion bottles to squeeze air out, then bags in boxes that collapse as air removed, now,back to glass via small glass bottles with no air in them.

I am glad I skipped the marbles in the bottle after recently reading here about how hard it is to get the marbles out of the bottle. I suppose using a large mouth bottle it would be OK, but a lot of extra maintenance cleaning marbles.

I just (yesterday) got myself set up with a Nitrogen tank and regulator. Have to get a hose and nozzle yet. My wife will also use it for her paints. She will probably use it more than me. This will server, for me, when the small bottles are not usable, as I anticipate color chemicals will require a different method of mix and use.