YGK Nitlon DFC is 100% fluorocarbon, made clear and hard for maximum abrasion resistance, durability and invisibility underwater. Fluorocarbon is far more dense than nylon, making for superior abrasion resistance, and has an index of refraction very close to that of water, meaning it's near on impossible for finicky fish to see your line or leader. Nitlon DFC is equally suitable for both main line and leader. Nitlon DFC is the first choice used by many light tackle fisherman when fishing tight around snags or structure, the high abrasion resistance also makes the heavier Nitlon DFCs (20 - 30lb) perfect to use when fishing reefy or coral areas. Nitlon DFC comes in 100m spools and available from 3lb - 20lb, and then the 70lb is on 70m spools. Nitlon DFC is a very high quality fluorocarbon that is made in Japan and has proven deadly on all manner of species.