After trying out several different types of Chinese knotting cord we have finally found one we love. This nylon cord has nice texture that helps to hold knots in place. To keep it from fraying you can melt the ends with a Thread Burner, or use Hypo-Tube Cement or super glue.
I originally thought this cord was narrower than some I had from another company--but when you use them in kumihimo braiding--the size of the braid still turns out about 4mm in diameter. I was able to use this cord interchangeably with the other brand. :-)