We took our revolutionary AST Plus slickness additive and put it into the our 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 our 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. Features the revolutionary AST Plus slickness additive for superior shooting ability and increased durability Utilizing the tapered belly from Infinity, Trout GP has a slightly longer front and rear taper and ¼ size heavy weight scheme. Compared to Infinity, Trout GP leans more finesse but is still a capable general purpose trout line. The choice for anglers who don’t consistently fish heavy rigs like large streamers or bulky indicators. Braided multifilament core