Seaguar STS Trout/Steelhead Fluorocarbon Leader Material is a genuine 100% fluorocarbon leader material that delivers incredible abrasion resistance and maximum knot strength. The STS Trout/Steelhead Fluorocarbon Leader Material features smaller diameters than monofilament. The lower light refraction makes for a significantly less visible line under water. The STS Trout/Steelhead Fluorocarbon Leader Material also sinks quickly getting your presentation down.