New material having the same light refraction as water, virtually disappears in the water. Impossible for fish to detect. Much harder than mono and a much more smoother surface than mono. Probably the best leader material on the market today. If you've got fish that are really shy, better start making your leaders out of Fluorocarbon, then watch your catches improve way above your highest imagination. Great for trolling leaders also! PLEASE USE BELOW ITEM NUMBERS IF YOU PLACE AN ORDER BY PHONE