Silver Thread Excalibur is the strongest, most abrasion-resistant copolymer line on the market, period If you"re looking for a line to withstand the punishment big fish can dish out in heavy cover, this line is it. Developed by polymerizing multiple nylon monomers, Silver Thread Excalibur is stronger and more stable. Plus, its diameter is consistent throughout the entire spool. What does this mean to you? Better quality, innovative technology and the best heavy-duty fishing line available.