Fly Shop Fluorocarbon too expensive? Try InvizX

by | Aug 11, 2020 | 39 comments

** Note ** This Troutbitten article replaces one from 2019 about Seaguar Finesse. Seaguar halted production of Finesse in 2020, and after much searching, fishing and testing, along with the Troutbitten crew, I’ve landed on InvizX as my go-to choice for terminal tippet. Here’s why . . .

I was halfway into the canyon and at the tail end of a warm fall day on the river.

With an hour left before the walkout, I heard a branch snap behind me. So I turned toward the rustling but continued my tight line drift, leading the nymphs with a high rod-hand to stay in touch.

I found Sawyer standing above me on the tall bank, hands on his hips, smiling and satisfied behind his dark lenses.

“Well, how was it?” Sawyer asked without moving.

“Good!” I replied and pointed downstream. “I caught three off that far bank below, and a couple right next to this . . .”

“No. I mean the fluorocarbon,” he said.

“Oh,” I nodded. “Yeah, I’m sold! I’ll never nymph with nylon again.”

Ten Plus

That was over a decade ago. Earlier in the day, Sawyer had given me his stack of fluorocarbon when I’d lost my own tippet holder spooled with nylon. Before that day, my skepticism and thriftiness kept me from buying in — from dishing out the $50 – $100 it would take to convert to fluoro. I thought I did just fine with nylon.

I did. And I’m still not so sure that flouro catches more trout under the surface. Some use it because it’s less visible and sinks a little better, but I use it because I have the chance to make more casts and keep my line in the water longer with fluoro. Here’s what I mean . . .

I use fluorocarbon for underwater presentations because the material takes more abuse. Its abrasion resistance and greater strength per diameter allows me to fish more aggressively against the structures where brown trout reside. Sure, I hang up, but I break off less. Flouro also has an uncanny way of releasing the inevitable twists and tangles of tippet that happen on a trout stream. Where I used to reach for the nippers with nylon, I now expect loose knots and loops to come out with marginal effort — and the few tricks of an amateur magician.

READ: Troutbitten | Let’s talk about tippet — Three questions about the end of the line in a fly fishing rig

Too bad we can’t nymph with this. Photo by Austin Dando


But let’s get back to me being cheap. I’m okay with that. I spend money where I must and cut corners where I can. And most long-term fishermen I know are the same. So the price tag of fly shop fluoro has always seemed a bit much to me, and I keep my ear to the ground for alternatives. For many years, my friends and I have used fluorocarbon that is marketed to gear fishers. We buy three to four times as much fluoro on a larger spool and then wind it onto small tippet spools. Years ago I settled for P-Line Halo, FC Sniper from Sunline, or Seaguar AbrazX. These were the best options among a host of other brands tried.

The trouble with these cheaper lines is threefold. Their breaking strength is inferior to the fly shop brands, they’re often stiffer, and the manufactured diameters only go down to about 4X — usually.

For a few years, Seaguar manufactured Finesse, and it was far better than the other big-spool fluoro options. It was my go-to choice for terminal tippet for a long time, and when Seaguar discontinued it, I felt a bit lost. Then Grobe told me he was fishing InvizX.

READ: Troutbitten | Fly Fishing Gear: What to spend on and what to skimp on

Matt Grobe is a good friend and Pennsylvania native now living in Montana. He chases big wild brown trout, mostly by nymphing them on a Mono Rig. Both Grobe and I agree that taking the fly to the trout is the most consistent way to catch the biggest fish in the river. Having them chase a streamer is fun, but I’ll put my money on an excellent nymphing or crossover approach most days. Grobe catches bigger, badder wild trout than anyone I know. So when he told me he was fishing InvizX, I listened.

Yup, Matt caught it on InvizX

Grobe uses Seaguar’s thinnest version of InvizX for his 5X. And now I do the same. But when I first saw the listed diameters and breaking strength, I balked, because I follow this stuff closely. Seaguar’s specs list InvizX .007″ as 4lb, but Matt assured me the line is underrated — InvizX is both thinner and stronger than it’s listed.

He’s right. I measured it to .0065″ and I estimate it’s breaking strength at about 5 lbs. (Stats on strength comparisons are below.)

InvizX is also softer, more flexible and has more stretch than most fluorocarbons, allowing the attached nymphs to move and wiggle at the end of the line. And that’s a good thing.

These days, a spool of fly shop fluorocarbon up to $20 for 30 yards.  So getting 200 yards on a spool of InvizX for $20 is a steal.

In short, Seaguar InvizX has become my go-to fluoro tippet material in 5X, 3X and 2X. (I use Orvis Mirage or Cortland Ultra Premium for my 4X.) InvizX is exceptionally strong per diameter, and it’s flexible for a fluorocarbon. InvizX is as good as some fly shop brands, and it’s far better than many others. And because the type of tippet we use is not what catches trout, I don’t overspend on tippet.

Buy Seaguar InvizX for 5X HERE

Buy Seaguar InvizX for 3X HERE

Buy Seaguar InvizX for 2X HERE

** Note ** The above links are affiliate links. Meaning, at no additional cost to you, Troutbitten earns a commission if you click through and make a purchase (of anything — not just fluorocarbon). So, thank you for your support.

Breaking Strength Per Diameter

How strong is your 5X?

While it seams like a fair question, the answer is not that simple.

What’s printed on the label may not line up with the facts. Breaking strengths and diameters are notoriously inaccurate in our industry. (A twenty dollar micrometer quickly reveals this.) And while fly shop brands like to exaggerate their line’s breaking strength and under-list its diameter, fluorocarbon marketed to gear anglers trends in the opposite direction — breaking strength are often far more than listed in the gear world.

In the end, what matters for fly anglers is breaking strength per diameter. We want to get the most strength available in a very thin line.

Where’s the X?

You won’t find “5X” printed on any of these spools, because X ratings are a fly fisher’s thing. The thinnest line from Seaguar InvizX comes in at .0065″, which is right in between the diameter of 4X and 5X. Oddly, Seaguar’s own specs round up to .007″ instead of rounding down to .006″. And truthfully, this is what turned me away from giving InvizX a chance, until Grobe told me I was missing out.

The Tug-O-War Test

When I bought my first spool of InvizX, I was impressed with the handling — the flexibility — for a 100% fluoro line. (Orvis Mirage is similar this way.) With a better flex, the attached flies can move more freely, and they appear more realistic in the drift. That’s a good thing.

And when I fished the InvizX, I was surprised by its strength. Clearly, the breaking strength is more than listed. So I did a long series of pull-tests with other fly shop brands, going head to head to see which was stronger.

I used a Davy Knot and tied each line to the eye of a #14 nymph. I pulled, and recorded which line broke. I retied both knots and did the test ten times for each line. (This long testing process required two beers.)

The results below are obviously un-scientific. But the micrometer measurements are accurate. I also tie good knots, and the tests were performed without bias. Some of these results are surprising.

♦  Seaguar InvizX (.0065″) is stronger than Orvis Mirage (5X at .0059″). And they are equal in stiffness.

♦  Seaguar InvizX (.0065″) is equal in strength to Rio Fluoroflex Plus (5X at .0064″). And the Rio is stiffer.

♦  Seaguar InvizX (.0065″) is weaker than Fulling Mill Masterclass (5X at .0069″). And the Masterclass is stiffer.

♦  Seaguar InvizX (.0065″) is weaker than Cortland Ultra Premium (5X at .0067″). And the Cortland is stiffer.

♦  Seaguar InvizX  (.0065″) is stronger than Trouthunter Fluorocarbon (5X at .0060″) And they are equal in stiffness.

♦  Seaguar InvizX (.0065″) is weaker than Trouthunter Fluorocarbon (4.5X at .0065″). And the Trouthunter is stiffer.

** These test results are only a comparison of InvizX to the other brands listed. They are here to give you some idea as to the relative strength of InvizX. This is not a full-range tippet shootout. And I’m not here to tell you what’s the best tippet available. A lot of factors go into that opinion, including cost, strength, diameter and flexibility.

Bottom line: I use Seaguar InvizX 4lb as my 5X, and it breaks closer to 5lb. I also like its handling and flexibility.

I use InvizX 6 lb for my 3X. And I use InvizX 8lb for my 2X. In my experience, all of them are much stronger than listed.

(I use Orvis Mirage or Cortland Ultra Premium for my 4X.)

Nothing Smaller?

No. There’s nothing smaller than 5X out there that I would buy outside of the fly shop brands. I had FC Super Sniper in its thinnest diameter, but I couldn’t trust it for my 6X.

So, I still buy 6X fluorocarbon in the fly shop brands. (I like Orvis and Cortland right now.)

READ: Troutbitten | Why you may not need the crutch of 6X and smaller tippets

My standard nymphing rig ends at 5X (because I don’t like leaving flies on the bottom of the river). But when I nymph with #18’s and 20’s, I often do better with 6X. So the name brand stuff is in my vest. But my primary nymph and streamer work happens with Seaguar InvizX.

I’ll mention this too: I continue to use fly shop nylon for all my dry fly fishing, and I don’t see an alternative for that any time soon. The supple high-end lines with greater breaking strengths are worth the nominal extra cost of fly shop nylon.


Seaguar InvizX comes on a bigger spool, of course. And that kind of inconvenience isn’t for everyone. I transfer the InvizX over to empty tippet spools, right out of the box. It takes about ten minutes and a couple of spools, but then I’m set for a good long time.

So if that sounds like something you don’t mind doing, try the InvizX.

Fish hard, friends.

Photo by Austin Dando


Enjoy the day.
Domenick Swentosky


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Domenick Swentosky

Central Pennsylvania

Hi. I’m a father of two young boys, a husband, author, fly fishing guide and a musician. I fish for wild brown trout in the cool limestone waters of Central Pennsylvania year round. This is my home, and I love it. Friends. Family. And the river.

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  1. I used 4lb invizx for years before i switched to 5.2 finesse. In my hands the finesse is slightly stronger and limper at the same diameter, although I did not test scientifically. Guess it’s back to Invizx now, did not realize they had discontinued the finesse.

    • Hi Greg,

      Perhaps they improved the InvizX formula. I measured Finesse at .0067″ (compared to Invizx .0065″). To me, I found the flexibility to be the same. And I listed the breaking strength to be about equal. In ten tests, it was InvizX-4 and Finesse-6.


      • Good to know, glad you tested them side to side.

  2. Dom, thanks for this update. I managed to score some finesse late 2019 and early 2020 from your affiliate links and am good for this season. It’s reassuring to know someone has bomb tested the Invisz!

  3. Any tips on how to re-spool onto empty tippet spools without causing line twist etc?

    • Hi Stephen,


      Put the small spool on a stick or a pencil with tape wrapped around it to keep it snug. So when you turn the stick in your hands the spool rotates. Put the large spool between your knees or thighs with enough to tension to hold it there, but don’t overdo it.

      Just make sure the spools are turned so the line goes onto the small spool in the same direction as it comes off of the large spool. No big deal. Pretty easy this way.


  4. I used to use Invizx before I switched to Finesse. Now, I guess the circle is closing.

    Lately, I’ve been using Stroft for my 6x. It’s not fluorocarbon, but it is really good stuff: very strong, supple, and has great knot strength. I might try it in 5x to see how it compares with Invizx.

  5. Thanks much Dom…Absolutely loving your articles. Particularly the winter fishing tips.
    I’m a lake fly guy out here in Central Oregon but my winter trout home river is the Deschutes. Great stuff my good fellow. Just got me some suggested 5x Seaguar from your link

  6. Greatly appreciate your advice Dom, for a 5 on a scale of fly fishing experience your posts save me a lot of trial and error and in the case of InvizX, money. 4 and 6 pound tippett material will cover a lot of bases for me, and the cost savings will fund the gaps with Rio, Orvis et al. Wonder what you use theInvizX 2x for primarily? Nites, bass, big fish, or constructing knotted leaders? Have a great summer.

  7. Good to know. Got the Seaguar bookmarked now. MUCH cheaper than the Trout Hunter.

  8. Got the Seaguar bookmarked. Its’s MUCH cheaper than the Trout Hunter. Good one.

  9. Nice. I noticed I couldn’t buy saguaro finesse anymore. Glad you updated your recommendations

  10. Nice. I noticed I couldn’t buy seaguar finesse anymore. Glad you updated your recommendations

  11. Hi Dom. Quick question. How convenient is it to carry the larger spools of flouro while hiking a stream? Thanks for the great article.

    • Hi Vincent. The answer is that, to me, it is very inconvenient to carry the larger spools. I would not do it. Just respool the line onto standard tippet sized spools, as I mentioned at the end of the article.


    • I know there’s another article about re-spooling it, but for me that hassle isn’t worth it.

      My chest-pack (Umpqua Overlook) has a large stretch pocket in the front that perfectly fits the spool of Finesse (now InvizX). All my other tippets stay on your typical dispenser.

  12. great article . Been using iviz x for about 3 years now its everything you say it is.Inviz-x and davy knots a great combo.

  13. I hear so many swear by fluoro but I’m just not convinced. Trout always see the leader regardless of dia. or chemical formula. Flour works because its what you use. Doesn’t knot well and is typically much pricier. Not trying to start an argument here, but is there anyone who still believes in mono over fluoro?

    • Hi Rick,

      Thanks for the thoughts. I respectfully disagree. You said, “fluoro works because it’s what you use.” But no, I’ve decided that fluoro works better after many years of using nylon (what you are calling mono). The article above describes my reasons for using fluoro. I mention that I do not use it because of invisibility. Read above, and you’ll see why I prefer fluoro.

      You could also check out this one:

      Now, those are of course, my thoughts. And to answer your last question, yes, there are many anglers who believe that nylon is the better choice. Their argument is most often about suppleness. And I would agree with that point five years ago. But these days good fluoro can be made quite supple. You will find a lot of european anglers prefer nylon. But their needs, and their waters, are much different than mine.


      • I defer to your extensive experience with sub-surface presentations, so no argument there, however . . .

        On the Upper Delaware system, guides swear by fluoro for fishing dry flies.
        I love Rio Power Flex Plus NYLON (oops) and can’t imagine a single wild brown refusing a dry fly presentation because it isn’t fluoro. Drag free is the name of the game up top and I don’t understand how fluoro helps with that vs. leader style, proper casting and aerial mending. What’s your take on this?

  14. I’ve always considered flouro the same as that scent remover spray,I have zero confirmation that it works,but sure hope it does!!

    • Thanks for the suggestion! I just ordered a spool of the 5x and really curious to test it out!

  15. Hi Dom,

    Thanks for this article and all your many others. I did buy the Inviz X through your website and as I looked around your web site and shop I wanted to buy the C&F chest patch fly box but it said it was unavailable and they didn’t know when it would be back.

    I went to the C&F site and it looks like they replaced it with C&F CFA-50 chest patch and threader. I did buy it but after thought you probably didn’t get credit for it and that you would may want to update your shop so you do get credit from them.

    Btw, feel free to use this email to let them know my purchase was because of your recommendation.

    Thanks again for all your articles and information. You have made a big difference in my fishing



  16. Hi Dom,

    So there’s no 4X InvizX, but is there a 4X Finesse? Would that be the “6.2lb, .185mm” size? In case I was able to track down some old stock.

    Thanks for everything you do!


  17. Have never used fluoro for tippet, mainly because of the cost. Interested in checking out the InvizX. My question will the blood knot, Trilene knot and improved clinch knot I use now work okay with fluoro? Currently use Trouthunter nylon which I like but if fluoro will help get my flies deeper, quicker, worth giving it a try.

  18. Dom, have you tried Seguar Tatsu? I have been using 4lb Tatsu since Seguar discontinued Finesse and find Tatsu to be even limper than Finesse, which I like. Check out this video from FLW Bass Pro Brian Latimer on when he uses each line. Basically, he uses Tatsu for finesse, Invisx for power and abrasion resistance. The metaphor he uses is to think of Tatsu as dress pants and Invisx as blue jeans. Tatsu costs more ($33.99 vs $24.99 for 200 yards on Tackle Warehouse) but that is still multiples cheaper than premium tippet fluorocarbon.

    Seaguar, on its website, says it has introduced its Gold Label leader material in new sizes down to 2lb test with at diameter of .104mm which makes it equal to in diameter to 7x Cortland Ultra Premium fluro tippet. Gold Label in 4lb is listed at .148 mm vs .165 mm for Tatsu and .165 mm for Invisx. Seaguar says it is their thinnest line. Unfortunately, I have not been able to find any retailer who sells Gold Label below 15lb test to try it. Have you managed to get hold of any? 25 yards of 15lb gold label is listed at $18.99 so if this same pricing carries down to lower breaking strengths the cost is pretty much the same as Cortland Ultra Premium–which would, of course, defeat the whole purpose of looking for alternatives.

    Have you found fluorocarbon thinner than 4lb Seaguar that you like? I see that Maxima has a 2lb at .127 mm that is priced similar to Invisx.

    I understand your views on going lower than 5x and generally agree but there are times during low, clear, slow water conditions when I find using 6x or 7x mono with small nymphs and no split shot gets more strikes. Haven’t tried fluorocarbon in these diameters mostly because I am cheap and find stripping off 8′ of Cortland Ultra Premium 7x only to replace it after break offs a major psychological barrier.

  19. OMG I cannot believe this article thank you! Seguar Finesse I discovered a while back and just ran out of the 5.2 lb stuff.

    I was trying to do the research on what to do next since the other Seguar Flourorcarbons were all labelled 6 or 4 lb test. I was wondering about the Red since it seems to be a bit more stiff. I figured using that for tippet material joined to a mono leader would work fine.

    • Right on. I’m not a fan of the Red Label Seaguar. It’s not bad, but there are much better options for breaking strength and stiffness.


  20. Have you tried or tested Seaguar STS (salmon,trout,steelhead)

    • Hi Greg. No, because the diameters and breaking strengths aren’t right for me.


  21. You say it takes 10 minutes to transfer line…how many beers is that???,

      • Interested if anyone has found a suitable alternative for 4X?


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Domenick Swentosky

Central Pennsylvania

Hi. I’m a father of two young boys, a husband, author, fly fishing guide and a musician. I fish for wild brown trout in the cool limestone waters of Central Pennsylvania year round. This is my home, and I love it. Friends. Family. And the river.

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