Scientific Angler MPX Fly Line is replacing a classic, the gold standard in the Scientific Anglers lineup. From tossing small dries to slinging huge streamers, the GPX could do it all. But all good things must come to an end. Built a half-size heavy, the MPX taper starts where the GPX left off. Redesigned with more mass toward the front of the head, the MPX provides the same benefits of the GPX, with an added emphasis on presentation. The power is still there, only with an added bit of finesse. Meet your new best friend.