Scientific Anglers Amplitude Smooth Infinity Instructor Fly LineBased on the versatile and best selling Infinity taper, the Instructor line incorporates a multi color taper section with alternating colors for easier loop visibility. This helps teaching instructors and students see and refine their casting loop shape and trajectory to improve casting skills. The Instructor line tapered section has five color changes alternating between green, orange, and blue and the running line is blue.