RIOs high-performing MainStream Saltwater Fly Line is an all-purpose saltwater fly line perfectly suited for fly fishers fishing in temperate-to-tropical conditions for multiple species. This weight-forward floating fly line features a hard tropical coating that will not soften in the harsh tropical heat. RIOs MainStream Saltwater Fly Line is designed similar to the RIO Clouser line where a reverse compound taper and bullet front taper allows anglers to effortlessly turn over big, heavy flies into the wind. Color:Blue. Cancer and Reproductive Harm- www.P65Warnings.ca.gov. Type: Saltwater Fly Line.