# Rubber Strap Comparison ? Isofrane, Borealis, Cuda



## pacostagli (Dec 19, 2007)

*Rubber Strap Comparison - Isofrane, Borealis, Cuda*

Hi everyone,

I thought I would finally get around to writing up one of my first, if not my first, review. Here is a quick, but helpful comparative review on three rubber straps on the market today - Isofrane, Borealis, and Cuda. No Obris Morgan in this review, as I don't have any on hand.









*Price and Refinement*
-Borealis: $25 w/ buckle (directly sourced from Borealis in Portugal)
-Cuda: $55-$75 depending on buckle choice (easiest to buy through Benarus/Stevral)
-Isofrane: $129 (directly sourced from Isofrane/Aquadive)

For the price, you honestly can't beat the Borealis rubber. Granted, the strap is not quite as refined as an Isofrane, I personally could not justify the $105 price difference. For the price of one Isofrane, I was able to redo my entire rubber strap stock for five watches. The Cuda's are nice straps, but are the firmest of the three and show the most wear n' tear after little use. Borealis is softer and more pliable than Isofrane, but they're also noticeably thinner.

I say the Borealis is not as refined because:
1) The buckle is not as highly finished. One had some sharp corners which I took care of with some fine sandpaper which made it better than new, and Borealis promptly sent me a free replacement.
2) The threads can also be a little off on the buckles, however I have noticed screwing the buckle together a few times takes care of this. 
3) The keepers on the 22mm strap do not hold the strap as snuggly as I believe it should, they're a bit loose. However, this problem is not present on the 24mm version. When on your wrist, this doesn't seem to be a problem though.









*Dimensions *
Isofrane - 5.5mm taper to 3.4mm, .9mm lug
Cuda - 5.5mm taper to 3.6mm, 1.6mm lug
Borealis - 4.8mm taper to 2.8mm, .9mm lug

The Cuda strap is noticeably the thickest of the three. The Borealis is a bit thin for my liking, however it is very comfortable on your wrist because of this. The Isofrane is the sweet spot for thickness. I have graded the dimensions on the sole factor of lug thickness. Since the Isofrane and the Borealis have super thin lugs, they're able to fit on shallow lug watches, while the Cuda is far too thick to work. With only .9mm of space needed between the lug and screw/spring bar holes, the Borealis/Isofrane will fit more watches. My Steinhart Apollon for example - Isofranes and Borealis fit perfectly, however the Cuda would not even come close to fitting.















*Color Range and rubber quality *
Right now, Isofrane has the most color options. 
-Cuda: black, orange, green, gray
-Borealis: blue, black, orange
-Isofrane: yellow, green, teal, black, orange, blue (etc&#8230;?)

All the straps are made from vulcanized rubber, so none will really attract dust. The Borealis are quite new (got them less than a week ago), so we'll see how they hold up. To date, the Cuda seems to show the highest level or wear and tear, despite minimal use. Isofranes are holding their own and show little to no use after being occasionally used in rotation. 
As you can see in the photos, the orange and blue for Isofrane and Borealis are slightly different. Borealis's orange is warmer and less bold than the orange from Isofrane. The blue from Borealis is more blue IMO than the deep ocean blue from Isofrane. In my mind, if I'm buying a blue rubber strap, I want it to look blue and not almost black.





















*Overall*
In the end, it obviously comes down to personal choice. I have been an Isofrane guy for a long time, but I bought one Borealis to check it out and have since bought four more. I couldn't be happier. They stand behind their slogan, "the best vulcanized rubber strap in the market&#8230; taking into account the quality/price ratio." If you're putting the strap on an expensive watch, I'd buy an expensive strap (Isofrane). On a moderate to cheap watch, I vote Borealis all the way. Cuda's fall in the awkward "in-between" - they're kind of pricy for the quality and they're difficult to find.

*Quick note on customer service*
As I mentioned in the review, Borealis was great to deal with. Their customer care was quick and helpful. They eagerly wanted to help with the buckle issue I mentioned. Isofrane on the other hand, I emailed them a few weeks ago to get a new screw (thought I had lost mine, but since found it) and I reached deaf ears (or broken fingers, given it was an email.)

If anyone has specific questions about the three, I'll be happy to add to this or private message about it.

Best,
Paul


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## Level.5x (Jun 7, 2015)

*Re: Rubber Strap Comparison - Isofrane, Borealis, Cuda*

Thanks for the comprehensive review! I've been wanting one of these ISO-style rubber straps for about a month or two. I first looked at ISO of course, but when I realized they were $99+, I decided to check other avenues. ToxicNATO was next but they've been out of stock for a while. I just checked Borealis and they also don't have the 22mm black version in stock. I wonder if they get these made from the same manufacturer?

I look forward to picking one up once somebody has them re-stocked.


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## pacostagli (Dec 19, 2007)

*Re: Rubber Strap Comparison - Isofrane, Borealis, Cuda*

Happy to share - it's a good thing I had three types to compare. Small differences, but important ones. I was going to pick that one up as well, but Borealis said it'll be back in stock in about 3 months.


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## taike (Mar 7, 2014)

*Re: Rubber Strap Comparison - Isofrane, Borealis, Cuda*



Level.5x said:


> Thanks for the comprehensive review! I've been wanting one of these ISO-style rubber straps for about a month or two. I first looked at ISO of course, but when I realized they were $99+, I decided to check other avenues. ToxicNATO was next but they've been out of stock for a while. I just checked Borealis and they also don't have the 22mm black version in stock. I wonder if they get these made from the same manufacturer?
> 
> I look forward to picking one up once somebody has them re-stocked.


Get 22mm black from deep blue. Discount code cyber for 40% off. Be sure to get Hydro 91 which is pretty much identical to borealis, not hydro 55 which is junk.

Toxicrubbers are no comparison as they are stiff polyurethane like seiko z22


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## Nokie (Jul 4, 2011)

*Re: Rubber Strap Comparison - Isofrane, Borealis, Cuda*

Great review and pictures.

Not often someone does a strap comparison & review, so thanks for posting.


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## solex (May 31, 2013)

*Re: Rubber Strap Comparison - Isofrane, Borealis, Cuda*

Thank you for the review. I had a couple of OM's but had to sell them because they were too long. My wrists are ~ 6 3/4" long and I really like the ISO look do you have any comment on minimum wrist size and the ISO and Borealis?


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## pacostagli (Dec 19, 2007)

*Re: Rubber Strap Comparison - Isofrane, Borealis, Cuda*

I believe the minimum wrist size for an Iso is 7 inches given about a 45mm case diameter - just got home to do some measuring


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## solex (May 31, 2013)

*Re: Rubber Strap Comparison - Isofrane, Borealis, Cuda*



pacostagli said:


> I believe the minimum wrist size for an Iso is 7 inches given about a 45mm case diameter - just got home to do some measuring


I wish these companies would make a smaller strap...


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## BajaYeti (Jun 16, 2016)

*Re: Rubber Strap Comparison - Isofrane, Borealis, Cuda*

Great review! Thanks for sharing the information |>

I'm in the market for an orange Isofrane for my ProPlof 1200m to give it a period look. I prefer the orange of the Isofrance which I probably wouldn't have noticed without the side-by-side comparison, so thanks again for that.

Also... I contacted Isofrane with a question as a potential customer and heard nothing back :-(


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## welcomdmat (May 23, 2012)

*Re: Rubber Strap Comparison - Isofrane, Borealis, Cuda*

I just came across this through search -- thank you!

The color comparison is really helpful. I have been trying to use WRUW posts . . .


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## pacostagli (Dec 19, 2007)

*Re: Rubber Strap Comparison - Isofrane, Borealis, Cuda*

Courtesy of WRXtranceformed, the 22mm straps from Deep Blue fit the same as the 22mm from Borealis, leaving the gap due to loose keepers. They're probably identical straps from the same manufacturing source.


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## Blackdog (Apr 27, 2007)

*Re: Rubber Strap Comparison - Isofrane, Borealis, Cuda*

I found this thread through a search, thanks for the very detailed comparison.

I have an original Iso and just got a couple of the Borealis ones. IMO, they would be almost perfect replacements if they had tighter keepers.

They keep moving around and it can get annoying.

I'm seriously thinking about buying some spare keepers from Isofrane to replace the Borealis ones... The straps are virtually identical, so it should work. They charge some 10euros just for the keepers, but it would still be a bargain given the price of the Borealis.


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## Metin90 (Nov 20, 2015)

*Re: Rubber Strap Comparison - Isofrane, Borealis, Cuda*

Fantastic review, I have to say, even though I haven't tried others aside Isofrane, I find the Isofrane rubber to be sturdy and beautifully crafted even though it could be offered a little smaller.


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## Snaggletooth (May 11, 2017)

*Re: Rubber Strap Comparison - Isofrane, Borealis, Cuda*

Black SKX on orange Borealis.









Other than reviews such as this (excellent work by the way) I had no frame of reference for ISO/Borealis straps and their kin. However, despite it getting good reviews I was unhappy with the stock strap on my SRP777. It was sweaty and felt 'slimy', and I was always aware in a small way that it was there in contact with my skin. My attention was drawn back to its presence again and again which was eventually the catalyst for my search for a better performing strap. I dislike bracelets - too heavy & fiddly to adjust - and have a drawer full of NATOs which I like, but annoy me when they stretch in the water, so I started seeking out dive strap reviews. ISO seemed an interesting, if expensive, option. Then I read this review and, given the knock-down price, decided to give the Borealis a go. I'm so glad that I did. I have no experience with an ISO to compare these straps against, but I can't recommend them highly enough. They are extremely comfortable on the wrist with none of the sweaty feeling from the Seiko stack strap. Good presence on the wrist, but tapers in thickness so not too thick where the strap doubles/wraps over. Plenty of ventilation from the holes along the length of the strap and they are incredibly good looking from a dive-watch/watersports perspective - and no stretching when wet. I initially bought a black and an orange thinking I could swap them around my small collection of watches, but given the amazing price & performance I very quickly ordered another two in black so my watches can be permanently shod in this, the new strap of choice.

Cons? If I could I'd like to see a black buckle available to match watches such as my black SKX, and the keepers do feel a little loose as others have reported. However, the keepers have given me no trouble and don't seem to migrate once the strap is on the wrist, and who other than me is going to even notice that my black watch is on a strap with a stainless steel buckle, or even care?! Get over yourself Boy!

A great strap, remarkable for the price. Like Arnie, "I'll be back", for more. Great work Borealis, keep it up.


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## Southtown57 (Jun 16, 2017)

Thanks for the review. I've been thinking about picking up an Isofrane. But after seeing this I might just go with the Borealis.


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## drlvegas (Jan 2, 2013)

I purchased the Borealis and Toxic NATO both about a month ago because I was curious about them. As far as I can tell these two are identical--maybe made in the same place. The buckles are slightly different with the Borealis being a bit more sturdy. The Toxic NATO doesn't have it's name on the buckle; the Borealis does. Just an FYI in case anyone is looking at both.


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## drbojangles (Jul 8, 2014)

Great review!


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## cndbasshunter (Nov 27, 2017)

thanks. i just ordered 2 new borealis straps. can't wait to compare to crafter blue i ordered too.


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## n4rwhals (Jul 16, 2017)

Great review! I've only had one rubber strap and I always ended up sweating when I'm wearing it making it very uncomfortable. Did you have that issue with these straps?


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## mrlobaloba (Oct 9, 2015)

I know this is an older thread, but thank you it's very helpful.


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## Erauqs (Jun 2, 2019)

Great review, eager to try out Borealis on my dive watches!


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## Simon (Feb 11, 2006)

sadly none are long enough for a wrist over 8" - my wrist at 8.5" means ur almost at the end of the strap when you put it through the tang
the 75mm + 135mm is not enough - wish they offered 80 + 140


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## RainMan 777 (Mar 26, 2012)

*Re: Rubber Strap Comparison - Isofrane, Borealis, Cuda*

great helpful review


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## gychang03 (Mar 6, 2015)

Great review! Thanks for the info


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## alexels (May 14, 2011)

Yesterday my Borealis arrived (22mm black) and the buckle is really poorly finished:

1. The inside edges were so sharp that I managed to cut my skin.

2. The depression where the tongue sits has irregular edges:









3. And top of the buckle looks like hasn't been finished at all, I can definitely see the marks where the metal was cut:









I emailed Borealis asking if this is the kind of quality that is to be expected from their buckles. Their reply: "The buckles are all hand made so no buckle is the same".


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## KidSalami (Jul 9, 2020)

Just received my black rubber, 20mm Borealis. The first thing I did was lay it next to my black rubber, 22mm Isofrane. I'll be honest, folks, I was hard pressed to tell the difference between them (other than the width). My wife even asked why I had two of the same strap...

The finish of the two straps is practically identical. Even the thickness and softness are almost indistinguishable. The Isofrane buckle is nicer, but, again, not by much. Unlike Alexels, my Borealis buckle had no flaws to speak of.

For $30 shipped to the US, the Borealis strap is a tremendous value. Quite frankly, I don't think I would buy another Isofrane unless they offered a color Borealis didn't.


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## hrant (Jun 21, 2015)

I've purchased rubber straps from Zealande (France). The quality is excellent but priced a little higher than competitors. However, I have no regrets.


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## agardnerf (Nov 19, 2019)

Customer service is everything, thanks for the heads up.


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