Transform hanks or skeins into compact balls that sit nicely while you knit and crochet. Use the clamp to easily attach the ball winder onto a table to quickly and easily wind your ball into a neat, center-pull ball. Best when used in tandem with a Yarn Swift. Ball winder holds approx. 100 grams or 3.5 ounces of yarn. Note: The metal yarn guide arm comes folded against the ball winder for shipping. The guide arm needs to be moved and positioned opposite the winding handle for correct operation.