I had this image in my head as to what her collar would look like. What I wanted was a simple circle, nothing fancy. You would be amazed how hard that was to find!
After spending what had to be at least three hours searching the internet, this is what I found. It isn't it exactly, but it's close. Choker Necklace. This necklace does not have an actual claps, and her collar does. Hers is also white gold where as this one is sterling silver.
I'd had some requests for a visual, and I hope this helps.