Scientific Anglers Sonar Saltwater IntermediateSlow sinking fly line for saltwater Its not very often youll need to fish topwater flies in the salt. Thats where an intermediate line comes in handy. The SONAR Saltwater Intermediate fly line features a slow sinking clear head that cuts through the surface and provides an amazing amount of stealth for those wary fish cruising the flats. From redfish and bonefish to permit and tarpon, give yourself an edge that fish wont be able to see. Slow sink rate