This jumbo flyer fits on Louet wheels with Irish tension. (It does not fit the Victoria or Julia.) Bobbins that fit this flyer will hold 9 to 14 oz. of yarn, making plying or spinning very bulky yarns easy. The flyer arms are fitted with hooks to adjust the position of the yarn filling the bobbin. You must have this flyer to use the bulky Louet bobbin. Bobbins are sold separately.