Seaguar the inventor and world leader in fluorocarbon and premium fishing line has introduced STS its first species-specific fluorocarbon leader material targeting Salmon Trout and Steelhead. STS is 100% fluorocarbon leader material that delivers incredible abrasion resistance and maximum impact and knot strength all with a smaller line diameter than monofilament. This fast-sinking line gets you in the "strike zone" quicker - and with a lower refractive index than monofilament line it is significantly less visible underwater.