Scientific Anglers Amplitude Smooth Infinity Fly Line

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There’s a reason we call it the Infinity: there is no end to what you’ll be able to do with it.

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Product Description

The Amplitude Smooth series of lines are, simply put, the highest-performance smooth fly lines in the world. With up to five times less drag and eight times the durability of traditional lines, this will change the way you look at fly line performance.

The conventional wisdom in fly fishing is that there’s no such thing as a “do it all” freshwater line. We have something to say about that. The Amplitude Smooth Infinity has the power to bomb out streamers, yet retains delicacy for dry flies. It mends like an absolute dream, and delivers flies at all distances. Built a half-size heavy, with a long head and substantial front taper, it’s perfect for everything from trout and panfish to pike and steelhead. There’s a reason we call it the Infinity: there is no end to what you’ll be able to do with it.


  • Features the revolutionary AST Plus slickness additive for superior shooting ability and increased durability
  • Extremely versatile general-purpose taper designed for most freshwater species; and excellent line for trout, grayling, panfish, bass, carp, steelhead, salmon, and pike
  • Made a half-size heavy to load fast-action rods, but works well with a variety of rod actions
  • Extended head length for long-distance casts and superior mending ability
  • Excellent for dry flies, nymphs, and streamers
  • For use in moderate and cold climates
  • Braided multifilament core


Customer Reviews

Based on 3 reviews
Dennis Arbogast
Fast and precise

This line really does shoot well and cover a multitude of conditions for trout. I've been through Rio and other SA lines but think this is the best for my Colorado lake and stream fishing. Floats well and rarely needs additional dressing. Most times I'm casting with a medium-fast 9', 4 weight Scott rod and still manage to reach where I want in medium wind. I'm going on season 3 with this line and will be back for more when outfitting another rod or I goof and step on it with my cleated wading shoes (pilot error) : (

Jay Rael
Smooth line - Big difference.

The Trout's staff recommended this line for my new rod set up (4wt Scott G Series) and I could not be happier! I love how smooth it casts. I was able to run a two-nymph rig with this line day at Deckers and it performed well. The line was very responsive and gave me the confidence to move through new lanes in the water and still get great drifts. Before this line, I had the perspective that any floating line will work. I was wrong, this line made a huge difference in my presentation and ability to get to different sections of water.

Jim Payne
Smooth smooth smooth

Having a nice line for me has made a huge difference in my casting accuracy and distance and this one fit the bill for me big time on the 9' 5wt. I've been teaching some friends to fish and I always start them on this outfit. Highly recommend spending a little extra on a nice line like this one

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