[Cross-posted from Grand, Unified, Empty. This is not an incentivized review; nobody at O2 even knows I’m writing this and none of the links have referral tracking. This is not medical advice, I am not a doctor, etc.]

Like many of you, I’ve been wearing a reusable cloth mask for just under a year now to protect myself, and others, from COVID-19. Cloth masks work well, and remain far better than nothing if they’re what you have available. However, with several more-infectious COVID variants now circulating and no end in sight due to vaccine delays, I decided I could probably be doing better. Enter the O2 Curve.

I had originally intended to purchase an N95-certified mask, but I quickly found that Amazon search results for “N95 mask” are effectively useless – too many fraudsters have realized that adding the word “N95” to things which are clearly not certified (and sometimes aren’t even masks) is a great way to get more hits. After poking around the internet, I stumbled upon the website of O2 Canada which promised an effective (though technically not N95-certified – more on that later) respirator mask, backed by publicly available filtration and testing data. I decided to give it a shot.

I’ve now worn my O2 Curve several times, including for a nearly one hour trip to my local grocery store, and the verdict is in. I love it, and I’m not going back to cloth.

Masks and Respirators and N95, Oh My

The first thing to mention, since it bears clarification, is the difference between a regular face mask and a respirator, and what N95 certification means in all of this. A face mask (cloth, surgical-grade, or other material) is just something that sits in front of your nose and mouth, usually held in place by looping around your ears. Face masks are effective at filtering the air which passes through them, but they do not form any kind of seal. This means that air (and virus particles) can escape or enter around the edges of the mask. Due to the lack of seal, and the way air flows when you breathe, wearing a mask does a great job of protecting other people from your air but is somewhat less effective at protecting you from other people (unless those other people are also wearing masks, of course). As I mentioned before, masks are far better than nothing; even cloth masks cut COVID infection rates by half or more when worn properly, and surgical-grade masks do significantly better than that. However, respirators do even better.

A respirator is a mask that forms a proper seal to your face, forcing all the air you breathe to pass through the filter. Think like a military gas mask, although of course modern commercial respirators are significantly less bulky and awkward than that. Respirators do tend to be a bit bulkier and more expensive than simple masks, and tend to require some adjustment at first; everybody’s face is shaped a little bit differently, and if you don’t get a proper seal then you might as well just wear a mask. But when worn properly, a respirator will provide full, symmetric protection for both you and anybody who breathes your air. In addition, since they require a little more investment they also tend to come with more effective air filters in the first place.

(There are several caveats to this of course. A respirator still only covers your nose or mouth; it cannot protect you against viruses or other particles which enter through e.g. your eyes or ears, and it cannot protect you against viruses transmitted by touch. It’s also worth noting that many commercial respirators have exhalation valves to improve breathability, which effectively prevents any filtration for air you breathe out. These respirators should not be worn for COVID protection without some kind of valve plug.)

Finally, N95 certification is not a third kind of product. It is a certification by the US government that a given mask or respirator is capable of removing at least 95% of a certain class of particles from the air that passes through it. Masks and respirators can be N95-certified, but it is not a requirement; it is quite legal to sell a mask with more than 95% efficiency without having it certified.

So where does O2 sit in all of this? The O2 Curve is a respirator (i.e. it forms a proper seal with your face) that is not currently N95-certified, though claims filtration efficiency above 95% when worn properly. According to the FAQ and studies published on their website, the O2 Curve is incompatible with the standard N95 test mechanism due to its design, and they are actively working to design an effective testing mechanism. I will grant that this is somewhat sketchy, but seems to be legitimate as far as I have been able to dig; their FAQ provides a great deal of detailed information to back up this claim. And even if it doesn’t achieve 95% filtration for some reason, it’s still probably a big step up from a regular mask just because of the proper seal. It would be great if they achieved N95 certification, but I’m trying not to let the perfect be the enemy of the good here.

The Purchase

The purchase itself was fast and straightforward. I bought the basic O2 Curve, a pair of valve plugs (which the website helpfully recommended, since the Curve does have exhalation valves by default), and an extra pack of 5 “Max Air” filters. The basic Curve comes with a starter pack of 3 filters, but the Max Air type are recommended for easier breathing when used with valve plugs. If you’re feeling fancy, the website also lets you splurge on fancy coloured shells for your Curve, but I stuck with basic white.

I submitted my order last Friday evening; I got a shipping notification the very next morning (a weekend!) and the package arrived Tuesday morning right on schedule. The box was very compact, and felt high-quality, more like a smart phone or smartwatch box than anything else. This maybe isn’t surprising; O2 is headquartered in Waterloo, Ontario, which is known for its high concentration of software and technology companies.

Initial set-up was very straight-forward. It took a minute to figure out how to pop off the shell, but after that it was very easy to insert the valve plugs, insert a filter, and replace the shell. Besides the plugs, filters, and respirator itself, it also came with a handy little carrying pouch.

The Product

The O2 Curve is light but feels solid and high-quality. It comes in two different fits depending on your face shape, but the “Find Your Fit” guide on the product page makes it pretty obvious which one you should order. I ordered the “High-Bridge” version, and it fits my face very nicely.

The straps fit around your ears and then snap together behind your head. It’s quite finicky to adjust at first, but this seems to be necessary; you have to adjust the straps along several different dimensions in order to form a proper seal without putting too much pressure on your face. I spent fifteen minutes fiddling with it when I first got it, and then another fifteen minutes adjusting it after I’d worn it for the first time. These two attempts were enough; it was quite comfortable the second time I wore it. This second trip lasted for about an hour, and I would have happily worn it another hour by the time I was done.

The seal, as far as I can tell, is perfect. I can’t detect any air escaping along the sides of my mouth or the bridge of my nose. If I really distort my face I can break the seal in various places, but the rubber adapts just fine to normal speaking motions and facial expressions. This is particularly important for me since I wear glasses, which are constantly fogging up when I wear cloth masks. The O2 Curve leaves just enough space for my glasses to rest normally on the bridge of my nose, and hasn’t caused my any fogging problems whatsoever.

The “Max Air” filters live up to their name, and are remarkably breathable when used with the valve plugs in. I wouldn’t necessarily want to do jumping jacks wearing it, but I probably could in a pinch. I was able to carry a bag of heavy groceries the kilometre and a half from the nearest grocery store to my home, and it wasn’t something I even thought about until I sat down to write this review.


Overall, I’m very happy with the Curve, and I will continue to wear it instead of cloth masks for the foreseeable future. It’s quite a bit more of an investment compare to the cheap cloth masks flooding the market (the basic Curve starts at $50 Canadian) but the additional protection of a proper respirator seems well worth it. (For me, frankly, it would be well worth it just to stop my glasses from fogging up). The proper seal and headstrap also means that it basically never slips or needs adjusting, and is overall just less irritating to wear. The only downside I’ve found so far is that the plastic shell makes it impossible to scratch your nose.

If you’ve been wearing cloth or surgical masks so far, I recommend upgrading to a proper respirator like the O2 Curve (with the necessary valve plugs). In my opinion the protection, convenience, and additional peace of mind make it well worth the money.

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4 comments, sorted by Click to highlight new comments since: Today at 10:45 AM

I got one of these, based on this post, and think it's great.

Sadly, O2 industries is apparently dead. From their home page just a few minutes ago:

Notice on Store Closure

After a court-appointed receivership and effective immediately, O2 Industries Inc. has ceased operations and will no longer be selling the O2 Curve and all O2 Curve related accessories including filters.  Any orders placed after July 30, 2021 that have not yet been fulfilled have been canceled and refunded.

Even more sadly, they also broke links to their support info.

I just asked a question about how to clean the respirator (NOT the filters):

Are you able to talk normally in it? The pictures make the lower jaw fit look really awkward.

I didn't have any problems once I found the right 'seat' to have it on my face.


Yes. I haven't held any really extended conversations, but I've spoken to a few people now without problems. Apparently it makes your voice sound kind of tinny or echo-y from the outside, but still quite intelligible.