Seaguar STS Fluorocarbon Leader Fishing Line -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. STS (Salmon, Trout and Steelhead) is the first species-specific fluorocarbon leader material targeting those speciesDeveloped for fishing applications where strength, abrasion resistance and virtual invisibility are paramountMaximum impact and knot strength with fast sinking line to help you reach the "strike-zone" quickerSize: 100 Yards