100% fluorocarbon, 100% stealthy and strong. Seaguar® STS Trout/Steelhead Fluorocarbon Leader delivers the knot strength, abrasion resistance, and near-invisibility needed to target finicky trout in the world's most challenging waters. Rocks, laydowns, brush – this line comes through the hazards more reliably than monofilament, and despite its smaller diameter, STS Fluorocarbon offers greater impact strength. Great in current; sinks fast to get your bait into the feeding zone quickly.