This is a lovely addition to my phone headphones. I simply used a 3mm (size 11) hook and some very beautiful variegated green. This was size 10 and I am sure I purchased it at Hobby Lobby sometime ago. I tend to take off the labels and stash away the balls into my knitting and crochet basket.
While I do not have quite so many as this, isn't it just beautiful to look at.
Just for fun how about the hook chart to compare. These are life-size.