Scientific Anglers took their revolutionary AST Plus slickness additive and put it into the brand new Amplitude Smooth Series. These lines are smooth like traditional lines, but have increased durability and slickness due to the AST Plus, which is mixed directly into their coatings.Each line is built with three colors to identify the separate parts of the line, and welded loops for quick and easy rigging.SA Amplitude Smooth Lines are simply the finest smooth fly lines in the world and are available in a number of freshwater and saltwater specific tapers.