Thats a yarn swift, not a ball winder. That part just holds the hank of yarn so it doesnt get tangled while you use a ball winder to make a center pull cake.
if you want a swift, you can majke one from about $8 worth of supplies from home depot. Google homemade yarn swift and lots of options will pop up. I made mine in about 20 minutes. as for ball winders I have this one
http://www.overstock.com/Crafts-Sewi...1/product.html. I really like it alot.
In order to be able to really use the winder though you do need a swift. Its nearly impossible to keep the hank from tangling without one while you use a ball winder.