You can use any size yarn, but I recommend not using special fuzzy yarns because they will hide the ribbing – this stitch looks best with a standard yarn. I’ve used cotton, wool, acrylic, and more, and all have worked well, just not fuzzy yarns.

Hook
I recommend a hook that is a size smaller than you would typically use with your yarn – the ribbing turns out best when the stitches aren’t too loose.