Berkley Trilene Fluorocarbon Pony Spool - Trilene® 100% Fluorocarbon - Professional Grade is the ULTIMATE fluorocarbon fishing line PERIOD! Diameter for diameter it has the strongest impact strength of all fluorocarbon lines. It's the Ultimate in manageability and the ultimate in invisibility. With a similar refractive index as water, fish can't see it! It's easily the most sought after fishing line by most of the touring Pro's. Ultimate Impact Strength Higher Strength Per DiameterExcellent Manageability Ultimate Invisibility