RIO's Mainstream Saltwater fly lines are built to optimize rod performance for the everyday saltwater angler — featuring slightly heavier, shorter head lengths that load rods quickly and deliver flies with confidence. Constructed with the same rigorous production standards and quality control as every RIO line, each Mainstream is finished with a hard saltwater coating that resists heat and humidity, shoots cleanly, and holds up to the demands of the flats, the surf, and everything in between. A reliable, well-engineered line for anglers who want RIO performance at an accessible entry point.