These ones are hand-made by artisans in Mexico and ethically sourced through Verve Culture (whose name is etched into one of the loose rings).
They come in two sizes:
To use, put the chopped cacao and hot water in a mug or pot, hold the molinillo between your hands, and move hands forward and back to rotate, until the cacao is blended and looks foamy on top. These would go great with a hand-made clay mug.
For those seeking a quiet, introspective experience of making cacao, this is for you!