Held 2 strands of dk weight together. Not sure what the yarn was, I let my son pick it out. Because my boy is an outdoor type kid, I made this with a belt loop on the back rather than a strap. This way it just hangs off his hip (and will encourage him to WEAR HIS BELT!! Heh heh! Secret Mom motive). And then I made the boy sew the button on! He’s quite happy with this quick little project!