Post #987: All the masks I’ve ever loved.

Posted on January 31, 2021

That would make for a short post.

There are a handful N95 masks that I’ve tolerated over the course of the pandemic.

I figured I’d take a page or two to review those, with an eye on which ones you might be able to buy now.  Not a comprehensive review, but one with a certain amount of put-up-or-shut-up realism, as I’ve actually worn these during the pandemic.

Bottom line:  Of the N95-type masks I’ve worn, one is currently available through an industrial supply house, via what amounts to a loophole.  (3M appears to be restricting that to industrial use only, but this industrial supplier will sell to individuals.)  And one is readily available on Amazon, but only in lots of 50 (for $58).  FWIW, that one folds flat and is easy to send via U.S. mail.  The rest are either unavailable or unacceptable.


I’ve been wearing N95s for years.  I was just blissfully unaware of it.  I bought and used dust masks from the hardware store.  I trust 3M products.  And that’s what Home Depot sold for high-end dust masks — 3M N95 respirators.

When people started complaining that high-filtration masks were stuffy, hot, and unpleasant, I was like, well, duh.  Of course masks are uncomfortable.  Haven’t you worn one before?  And I guess the answer is no, because the only need outside of the hospital setting was for dusty manual labor.

I didn’t (and still don’t) see the sense in kvetching about it.  You just need to put  the discomfort into perspective.  Put it on a scale:

  • Sanding old paint:  3
  • Sanding old paint in summer heat:  5
  • Sanding old paint in summer heat wearing an N95:  7
  • Getting lead poisoning from sanding old paint without a mask:  9

And just like that, wearing an N95 doesn’t seem quite so bad.

As you can guess from this, I have zero sympathy for people who whine about the lack of comfort from effective, high-filtration masks.  It’s not that they’re wrong about the comfort.  It’s that they somehow think this is some novel, interesting, or even relevant insight.

I suspect that the complaints about comfort are from people who still don’t think they have a good reason to have to wear a mask.  Who still think that COVID isn’t that big of a problem.  Or that high-filtration masks don’t work.

So, having worn them for years, in adverse circumstances, when I read somebody crying hardship about having to wear a mask, indoors, in the air conditioning, while they shop, my only though is, cut me a break.

I’ve been thinking about reviewing options for N95 masks, because I see a lot of poor information (e.g., infomercials) out there.  I’m not qualified to review masks.  But neither are the authors of 99% of the mask reviews you’ll read.

To keep it real, I am only going to talk about masks that I have actually worn, in this pandemic.  This isn’t a comprehensive review, it’s limited to ones I have tried.  But, because I’ve worn them, it has a certain put-up-or-shut-up aspect that is sorely missing from most of the mask advice you’ll get on the internet.

General guidelines

References for finding specific masks are in the next section.

At the end of the day, for me, goodness-of-fit is the  make-or-break factor for most N95 mask candidates.  Does it seal completely against the face.  Does it keep that seal as you move around.  I have no way to test the actual filtration ability of mask material.  But I can definitely reject some masks based on their leakiness.  No tight seal means no N95 level of protection, full stop.

For that, 3M is the best in the business, by a wide margin.  I was also pleasantly surprised by the Kimberly-Clark duckbill N95 respirator, owing mainly to its great flexibility, stiff nosepiece, and behind-the-head straps.  I’ve tried some Korean FK94s (with behind-the-head straps) that are almost OK, and would do if I had nothing better to wear.  But I have yet to find a “KN95” ear-loop mask that has an acceptable fit.  As far as I’m concerned, none of the “KN95” masks I’ve bought so far provided serious protection.

A few other conclusions:

First, I infer (from the offers I’m seeing) that 3M is once again selling N95 masks outside of the health care sector, but only to industry, not to individuals.  There are abundant offers of 3M N95s, but only via industrial supply firms or, as in the case of Amazon, only as business-to-business transactions.  I found one industrial supply firm (Grainger) that appears to sell the standard 3M 8511 valved N95 respirator to individuals.  Just tape over the valve it if bothers you.

Second, the Kimberly-Clark duckbill N95 respirator remains my current go-to, easy-to-purchase N95.  It’s a pain to put on, but it seals well.  And you can buy them, in bulk, on Amazon for about $1 each.

One overlooked advantage is that this mask is easy to share:  You can mail them in a standard 8 x 12 envelope.  I bought a bag of 50 on Amazon a month ago.  I’m wearing my second one, yet I only have ten left in the bag.  The rest have been parceled out a half-dozen at a time to various friends who don’t have N95s and want to give these a try.

Want to encourage your friends and relatives to step up to N95?  Buy a bag on Amazon and start mailing them out.

Third, I bought a box of FK94 (Korean N95) masks from a reputable vendor.  I bought them as being the closest substitute available for the 3M 8210 masks that prefer but can no longer obtain (for the time being).  I can’t test them, but I believe these genuinely meet Koren standards.  Everything about them looks and feels correct.  And more to the point, I can’t believe there’s a big profit in the U.S. marketing of reasonably-priced high-quality counterfeits of a standard that nobody in the U.S. has heard of.

That said, the face seal on the FK94s that I bought is inferior to either 3M or the Kimberly-Clark.  The mask is too stiff, and the seal too uniform, to get a completely airtight seal around the nose.

I don’t know if that’s a generic issue with all KN94s, or just the ones I bought.   Or with my nose.  But I’m not going to try a different brand and/or rhinoplasty to figure that out.  It’s not a huge issue.  It’s a small leak.  I’d wear this FK94 before I’d wear a cloth mask.  Bbut I won’t be wearing these as long as I have a properly-sealing N95 alternative.

Fourth, I have yet to buy a KN95 that I am willing to wear as anything but a symbol of politeness.  I haven’t found one that will seal against my face, at all.  They do have an easy-on, easy-off advantage.  So I keep one in my pocket as I walk outside, for use if necessary.  But I’m sure the air leaks badly compromise the filtration.

These were all “hardware store” KN95s.  These are probably as good or better than (say) single-layer cloth masks.  And I haven’t yet bought a “serious” KN95 (one advertised as having an emergency use authorization (EUA) from the U.S. FDA).  But I just don’t think any ear-loop mask is going to provide the fit I need to achieve an N95 level of filtration.   YMMV.

Finally, I should probably offer my two cents on “double masking” with surgical masks.  I wouldn’t do that.  It all boils down to the tradeoff between the filtration level of the mask cloth, and the back-pressure that cloth generates (how hard it is to breathe through).

The higher the back pressure, the more you breath around the mask, rather than through it. And unless you’ve got a lot of sophisticated equipment, you can’t quantify that at home.

If you are using an actual surgical mask (with two rating numbers, BFE and PFE), the mask cloth itself filters as well as an N95.  The lower filtering efficiency of the mask is due entirely to the air leaks.  That’s how much breathing around the mask matters.

If you insist on wearing a surgical mask, and want to up your game, in my opinion, you are probably better off wearing one mask and wearing it in a way that minimizes air leaks.  That means using the “tied and tucked” method made public in a recent set of mask tests published in JAMA (Post #924).  That tied-and-tucked method is shown in this YouTube video.  Or adopting some other approach that holds the mask closely against the face, up to and including taping it to your face.

Reasonable people may differ on that.  But, for sure, if two masks isn’t twice as hard to breathe through — then you’re sending a lot of air around your mask.

Finally, squared, a lot of people want to belabor “fitting an N95 respirator”.  As if it were some sort of arcane ritual that mere citizens should not attempt.  (And yet, plausibly a million health care workers now put these on every day.)  Either I’m exceptionally stupid, or they’re making a mountain out of a molehill.  Put a finger next where the mask meets your face, breath out, see if you can feel air escaping.  Adjust the mask until the air no longer escapes.

If you want to go high-tech, lick your finger first.

I see people commenting on Washington Post articles, mentioning tests using (e.g.) powdered bittering agents and such.  I think those must be for full-face N100 respirators, as if you were in The Hot Zone.  I’ve read the manufacturer’s instructions for all of my N95s, none of them mention anything like that.  All of them tell you the right way to put it on your face, and some simple checks to perform.  It’s not really rocket science.

In fact, one of the things that convinces me that universal use of N95s would be good for America is the presence of (what I interpret as Russian) internet trolls flocking to any Washington Post article that suggests that.  All of a sudden, out of the woodwork, you have short comment after short comment on just how difficult it is for Joe or Jane Citizen to use an N95.  Complete with intense technical detail like those bittering agents which, for as long as I’ve been wearing them, I had never heard of.  I interpreted all that sudden chatter as a well-organized campaign to dissuade US citizens from wearing N95s.  Which is why I think everybody ought to wear one.


My pandemic, in six masks.  


First mask I wore:  3M 8511 vented N95 respirator.  With an extended discussion of buying from Amazon.


Plausibly currently available to individuals via the industrial supply firm Grainger, per this listing.


In the ancient past, I tried several N95 dust masks for use around the home.  In the end, the most comfortable effective mask for shop work, sold at the hardware store, was the 3M 8511.  That’s the kind with the vent, and that’s about as good as it gets, I think.  That was my go-to mask at the start of the pandemic.  I ended up handing out my supply, a few at a time, to people who needed a good mask but couldn’t get one at the time.

With the vent, it’s not really appropriate for hospital use.    Some places ban it under the notion that the vent lets out aerosols.  But, in fact, it’s as effective as most cloth masks at containing aerosols.  (Just FYI, it’s an N95 on the inhale, but only about an N50 on the exhale.)  It just looks bad.  If you want to use a 3M 8511, but don’t want to catch flak about the vent, just clearly tape over the vent.  Then it’s just a less-comfortable un-vented N95 mask.

There are some signs that this mask is once again becoming legitimately available.  My reading of the tea leaves is that 3M has put these back into business-to-business distribution channels only.  But that you can, if you work at it, find a business-to-business entity (an industrial supplier) who will accept individual orders.

But you have to be cautious about fakes.  Are there a lot of 3M counterfeits out there?  Just check out the numbers on the 3M respirator fraud page.)

Nothing reliable on Amazon for non-business customers.  On Amazon, these masks were all withdrawn from sale to the public very early in the pandemic.  Listings were marked “reserved for health care workers”.  But now, Amazon is allowing some listings for business-to-business (industrial supply) sales.

Here’s an illustration of the past and present, on Amazon.  The ones in red, you cannot buy unless you represent a health care organization.  The one in green, you can buy if you are “a business”.

I tried it, and Amazon definitely will not sell, from this listing, unless you register for a business account.  And they do some form of verification to see that you in fact have a legitimate business.  I had my own small business, and so I have (e.g.) a DUNS number and EIN for it, but I didn’t follow through with registering my business.  I have (or had) a legitimate business, but I’m not a legitimate business user of N95s.

Oddly, in addition to the health-care-only and business-to-business only listings, there is one Amazon listing for that mask, with many vendors who appear willing to sell to anyone, at a reasonable price.   These are typically listed around $2.75 per mask, in boxes of 10.  (In my experience, a box of ten will last you for years if you wear them an hour a day to go shopping.)

So, the question is, would you buy that mask, from those vendors?  Even though, elsewhere, Amazon appears to be strictly enforcing rules that restrict sales to health care entities and to business-to-business (industrial supply) transactions.

My answer is no.  As follows.  By just quickly checking one of the vendors.

The ad shows the picture of a 3M mask.  The comments say this is genuine 3M.  But the sellers willing to sell directly to individuals appear to be a collection of tiny, fly-by-night, totally marginal businesses.  None of which appears to have a main line of business related to shop supplies (which is what this particular mask is.)

Example:  One seller is “Allergy Be Gone”.  Click the vendor name on Amazon to see brief description, legal name, and mailing address.  This vendor is claiming to be the leading allergy supply company in the U.S.A.  Which sounds great. But if you crudely track it down ( copy and paste the legal name and address to Google and search for it), the address is a small house in New Jersey.  So you have to ask, is this really the leading allergy supply company in the U.S.A.?

No?  Then how did this marginal enterprise manage to get boxes of genuine 3M N95 respirators, in this climate?  I’m not saying it’s impossible.  They may have (e.g.) legitimately bought them in a business-to-business transaction, and are retailing them … for about the same price they paid for them?

So, I can’t tell if these are counterfeit.  But I am saying that this is a risk.

I’m not buying from that vendor. And this gets to my general rule about buying from a listing on Amazon:  Illegitimate vendors are like cockroaches.  If you spot one, there are certainly others lurking.

And now the punchline:  In my experience, there are no clearly legitimate unrestricted 3M N95 respirator listings on Amazon.  If it’s 3M, and it’s on Amazon, and it looks like Joe Citizen can simply buy it, in my opinion, there’s a good chance it’s a fake.  At the least, there’s a good chance that something is dodgy.

Can you legitimately buy this elsewhere?  Apparently yes, because some industrial supply firms will sell to individuals. 

Purely retail chains don’t seem to be offering them.  These are out-of-stock at Home Depot.  Unavailable at Lowes.  Unavailable at Sherwin-Williams.  Unavailale at the Web Restaurant Store.  Uline (a long-established industrial supply firm) only offers an off-brand substitute, not the actual 3M mask.  ZORO, another industrial supply firm, has a full range of N95s, but if you try to register, they require a company name.  So this also appears to be restricted to business-to-business sales.

All of that is consistent with 3M putting these back into industrial supply channels, but not retail channels.

But Grainger appears to be willing to sell you a box, with guest checkout, per this listing.  Oddly, of the roughly 100 N95 respirators listed, this is appears to one of just two or three currently available.  I got as far as giving them my credit card number, without a hitch.  But I didn’t actually buy a box just to check them out.  Grainger is an old-line industrial supply firm, and I would trust Grainger to sell me the genuine article.

My conclusion is that 3M has once again started releasing these for sale, but only through business-to-business (industrial supply) channels.  None of the big retail vendors (home Depot, Lowes) appears to have them.  That said, it appears that individuals might be able to buy this respirator through some business-to-business channels, where the business-to-business supplier also offers sales to individuals.  At the last, it looks like you can order them (at about $4/mask including shipping), from Grainer.

Second pandemic mask:  3M 8200/8210/8211 unvented mask-style N95 respirator.

Source:  Lowes.

Not available currently, as far as I can tell, except from one Far-East vendor, or if buying in very large lots.

Once the pandemic was in full swing, and all the 3M respirators had been removed from the shelves, I got a little self-conscious wearing that vented 3M 8510.  It’s a mask that shouts “suitable for medical personnel”.  And so, even though mine were out-of-date, in an open box (so no hospital would accept them), I put my 3M 8510 in a drawer and began wearing a (now-discontinued) version of the 3M 8200.

The advantage of this one is that it doesn’t look like “an N95 respirator”.  It functions as one.  But it’s a lot more low-key about it. Particularly if the printing is faint, as it was on the ones I had.

Near as I can tell, there is no U.S. source for these selling to the general public.  You can, in theory, buy a box of 160 for about $400 on Amazon.  (Pre-pandemic, these are about $1 each).  I didn’t follow through on that.  Otherwise, I saw no US source offering these.

I liked this mask so much that I replaced the elastic when it broke.  I eventually wore out the filter medium.  When that happens, the electrostatic cloth gets clogged with particles making the mask hard to breathe through.  At that point, the only option is to toss them.  And by that point in the pandemic, I only had one of those, having given away the rest of my small supply.

Third mask, from mid-summer:  A D-I-Y mask using a 3M Aseptex surgical mask plus 3M Filtrete filter material.

Not for sale, but easy enough to make one if you have a good cup-type dust mask on hand.  Those cup-type masks are now back for sale at Amazon.

By late summer I could not find an N95 mask for sale that I could trust to be genuine.  So I made some (instructions are in Post #780), starting from a 3M Aseptex surgical mask (which I had for use as dust masks), and adding 3M Filtrete cloth from a high-end 3M HVAC air filter.

This worked ridiculously well.  The 3M Aspetex surgical mask has the same shape of face seal as their N95 masks, so it gave a good seal against the face.  But it does not filter aerosols.  Hot-gluing a piece of high-end Filtrete filter material around the Aseptex mask provided a known aerosol filtration capability.

Best guess, this was somewhere around an N90 mask, between the surgical mask and the Filtrete.  And this was, by far, the most breathable and comfortable “N95” mask I have worn.  The 3M Filtrete produces almost no back-pressure.

I still wear one of these from time to time, but the Filtrete material tends to shed fibers when used this way.  I should “encapsulate” it, as I did for my Filtrete mask liners (Post #807).  But by the time this mask started getting ratty, we could buy N95s again.  So I’ve never gone back to making those masks.

Fourth mask:  KN95s from the hardware store.  Complete fail.

I tried three different brands.  All were a complete fail from the standpoint of protection.  Could not get any of these to seal.  And, of course, I have no idea if they actually filter as advertised, if I could get them to seal.

I never did buy or try a mask certified to be on the FDA emergency use authorization list.  Plausibly, those would be better.  I don’t know.


Fifth mask:  N95s slowly return to the marketplace.  Kimberly-Clark duckbill N95.

Available in bags of 50 from Amazon, for about $1 per mask.  And, likely, elsewhere in smaller quantities at a higher price.


These masks meet the NIOSH N95 standard, but they are not certified for medical use.  And that’s fine.  N95 is N95, it doesn’t matter if it’s a “medical” N95 or not.  Medical masks must (e.g.) resist fluids as well as capture particles.  Near as I can tell, in more normal times, this mask is generally sold for industrial use, particularly in the food supply and food service industries.

The only thing not to like about this is that it’s fairly awkward to put on.  You have to grab both straps, pull them back, put it approximately on your face, let go of the straps, then adjust everything.  It takes longer than most masks.

That said, once properly tugged into place, it’s flexible enough that I can always get a good face seal.  I feel 100% comfortable about the level of protection wearing this one.

And, as I noted earlier, it folds flat, so you can easily mail a half-dozen to friends and family.

Best guess, this thinner mask is only good for about eight hours of use.  At some point, mine seemed to be getting a little harder to breathe through.  So, at the risk of wasting some portion of $1, I tossed it and started wearing a new one.

Sixth mask:  Good, but not good enough.  “KOSHA certified” KF94 mask, via Amazon


First, the Korean OSHA really is called KOSHA in EnglishHere’s a discussion of the KF94 standard, from smartairfilters, an all-around excellent source of information on mask standards.

I have no clue whether this is legit or not.  The seller appears to be a small incorporated business located in a California industrial park.  The mask has all the right indicia.  The certification number appears to have the right form. But there was no way to dig up that certification number to check it.

I bought these because they have the same form factor as the 3m 8100s:  Mask-style respirator with behind-the-head straps. The mask appears very well made.  Metal nosepiece, thick elastic, and so on.  But in the end, this does not seal up quite well enough against my face to make me comfortable with the level of filtration.

I would wear this before I would wear a cloth mask.  But I would not wear this if I have access to a properly-sealing N95 respirator.