This is a leader line made of "Zylon," the strongest super fiber ever, finally released in 2001. It boasts approximately twice the strength of polyarylate (product name: Polylat), and its overwhelming strength, low elongation, and cut resistance make it the ultimate choice for attaching to large fish or for use as assist hook line. ●Belo spool ●Material: Zylon ●Specific gravity: 1.54