The listing is for a combination of ONE Medium size Yarn Swift and ONE Large Metal Ball Winder (10 oz). The medium size yarn swift can hold skeins up to 6-ft in circumference and is made of solid beech wood. It fits edges up to 1 3/4" thick. The super heavy duty metal ball winder can handle about 10 oz of yarn, which is 2.5 times of what our smaller winder does. The winder can be clamped onto a table up to 2 1/8" thick.