Kitty String is a world-class yo-yo string company that provides premium quality yo-yo string First Class XL – 100% Polyester XL is the Thickest among all Kitty String. XL gives a tighter bind and faster whip. This was designed for people who still feel that Fat type are bit thin for their play. XL upgraded the thickness to 13 Strands to make it even thicker and heavier for all types of division. Usually, XL are used by Single A division (1A) Strings are between 120 and 125 cm in length, so they are a good choice for those who like longer strings. In anticipation of being cut to a specific length, these strings do not come knotted, so you must tie your own finger hole.