I haven't tried
these, but I think I might for my next ferment. I wonder if anyone here has tried them.
I've tried marbles and water in plastic bags, also cabbage leaves, but because I make a mash out of my peppers before starting the ferment, smaller bits can still float to the surface and could potentially become contaminated.
For my most recent ferment, I found that using sufficient salt and starter keeps the nasties away and gets the ferment going pretty quickly. Once the ferment gets going, the head space fills with CO2 quickly and also keeps the nasties away. I also agitate the jar every day or so that most of the mash sinks back to the bottom.