Scientific Anglers Amplitude Smooth Infinity Plus Line

Scientific Anglers


It's not too often that we get really excited about a new fly line, but when we heard that this line was coming out we were really excited, and could not wait to get our hands on it and cast it. Our expectations were blown away after the first cast with the SA Amplitude Smooth Infinity Plus! Wanna hit the backing knot on a 100 foot cast? Wanna do it with ease every time? Pick up this line!

Scientific Anglers' Amplitude Smooth Infinity Plus fly lines are a scaled up version of the incredibly popular Infinity taper. SA took a good thing and made it better, or perhaps more versatile. The standard Infinity is a great fly line, but it doesn't handle really heavy loads very well. Now meet the Infinity Plus! The same great taper, but one size heavy for turning over heavy nymph rigs, big streamers, making long casts that punch through the wind, and is a roll casting, mending, hucking machine!  The long heavy belly of the Infinity Plus really loads rods into the sweet spot, without feeling too heavy or clunky. The rear taper of  this fly line allows the caster to carry a lot of line in the air and get a lot of line speed going, and when you make that last double haul and let this thing go, it goes! The shoot-ability of this line is just incredible. The front taper on this line is pretty standard, about 8 feet. Which turns over beautifully, but has the mass to turn over big streamers and heavy nymph rigs. This might be the most versatile fly line we've ever cast and fished. Whether you're rolling casting a parachute Adams on a creek with your 3wt, making a long stack mend with a double nymph rig on a big western river, throwing big bunny leeches to coho, or skating flies for steelhead, the Scientific Anglers Amplitude Smooth Infinity Plus seriously does everything! 

SA Amplitude Smooth Infinity Plus fly lines feature SA's AST Plus slickness additive which is proprietary to Scientific Anglers, and not only makes these lines incredibly slick, but it also makes their lines incredibly durable as well. Very rarely do you have to clean SA lines that have AST Plus. These lines remain slick for years.  

The color of the Amplitude Smooth Infinity Plus line is three different colors:  Mint Green, Buckskin, and Willow on the tip.

Here is what Scientific Anglers has to say about their Amplitude Smooth Infinity Plus fly line:

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.

  • Features the revolutionary AST Plus slickness additive for superior shooting ability and increased durability
  • A scaled up version of our general purpose Infinity taper, the Infinity Plus is built a full size heavy for the fastest rods and larger trout rigs
  • Underlining Infinity Plus by 1 size creates an AFFTA true standard weight for slower rods and advanced casters
  • Braided multifilament core
Scientific Anglers Amplitude Smooth Infinity Plus Fly Line Taper
Scientific Anglers
Line Weight
47' / 14,3m 90' / 27,5m 120gr/7,7g
48' / 14,6m 90' / 27,5m 140gr/9,7g
49' / 14,9m 90' / 27,5m 160gr/10,3g
50' / 15,2m 90' / 27,5m 185gr/11,9g
51' / 15,5m 90' / 27,5m 210gr/13,6g
52' / 15,8m 90' / 27,5m 240gr/15,5g

* Grain weight for the first 30ft