Rio Powerflex Plus Leaders are extremely strong. The new Powerflex Plus material is up to 20% stronger than comparable diameter size leaders. The new material improves on the nylon copolymer formulation. Are you a materials scientist? Me neither. We fish. In fishing talk we don't need copolymers etc. Let's try this- A Powerflex Plus 5x leader is a full pound test stronger than other leaders of the same diameter. That will make a big difference on the water. Try out the new ultra strong Rio Powerflex Plus Trout Leaders.