I found Cat's markers in Cat Bordhi Book One of her series New PAthways for Sock Knitters. At that time she was working with a designer to perfect them. They can be popped over the cable or slid onto a needle. To quote Cat, and they are beautiful. She is 100% correct!!
These were recommended by Cat Bordhi the inventor in her Book One of New Pathways for Sock Knitters. When she wrote the book, these were still in the development stage and I looked high and low for them....found them at Jimmy Bean's Wool! They are the perfect sock knitting markers!!!