Fluorocarbon line is the number one choice of leader for most anglers. Brands like Seaguar have dominated the Fluorocarbon market with top quality like. Fluorocarbon makes an excellent leader material because it is abrasion resistant and harder than most standard monofilament leaders. The other distinct characteristic is how close the refractive index of fluorocarbon is to water. This makes Fluorocarbon nearly disappear in water. This is important when fishing in clear or skinny water or when targeting line shy fish.