I call these toggles, not because they can fasten things - I just like the way the rings rattle back and forth as they're locked onto the glass spindle.
It's an amazing process - by which the rings are made one day - annealed, then put back in a cold kiln to bring up to temperature. Then a base bead is made with only one end, and while it's still hot enough not to shock and crack - yet, cool enough not to have the rings stick to the hot glass, you retrieve the rings from the hot kiln, slide them onto the base bead and QUICKLY add that second end to the base bead... locking the rings onto the bead. Quickly, it's back into the kiln to anneal... then you say a prayer, in hopes that you did it right (and fast enough) and nothing cracks between then and the time when you pull everything out of the kiln after cooldown. Then and only then, you take a deep breath.
THAT is why they bring the $$ they do. Plus, aren't they just beautiful??