That’s right four hundred forty masks (6 cents per). Yes it’s Amazon but this is a good deal.
This is the link: https://www.amazon.com/dp/B08J1THV9G
It is from a sub-company of Amazon that specializes in deals so it is legit-ish. The ones a close friend received came in an official 3M branded box (a huge brown box not retail packaging).
They’re individually packaged in the official sealed wrappers, had lot codes on them and looked to be in good shape. No weird smells either and the elastic and nose pieces seemed fine. No expiration dates unfortunately if that’s super important but the box had a barcode and I suppose you could contact 3M and ask about that lot number.
Checking into the lot codes from the photos I got according to a post on reddit (https://libreddit.privacydev.net/r/Masks4All/comments/168a53a/3m_aura_9205_respirator_lot_a202496_expiry_date/) the ones they received should have been made at the very end of 2020 (days/weeks before the new year) so with a 5 year official expiration date for the full NIOSH rating that puts the expiration of them at around December 2025. So as expected these are discounted because they’re “officially” expiring in the near term.
As long as you store them out of the heat (not in your 140F garage or car) and they weren’t too badly mistreated before this I figure the official dates are conservative estimates and with any luck they’ll still provide nearly all of their protection through at least the middle of 2026 and maybe beyond. Certainly better than nothing and probably safer than the bulk government resellers who break up these 440 piece boxes into 20 packs and sell them for $0.50 each.
To read the lot codes: first letter indicates country of origin factory, second and third characters (first two digits) indicate the year of manufacture, so 20 would be 2020, next 3 digits indicate how many days since the start of the year they were made (so 330 would be 330 days since Jan 1, 2020). Last one is the machine that made it.
If anyone can chime in on where that 5 year rating comes from that would be great (I know for a lot of drugs the maximum safe time is from tests done by the manufacturers and in their own interest they only test for a few, maybe 5 years and when the US military tested some substances they discovered they retained most of their potency for much longer). As I wouldn’t be surprised if it’s a case of 3M only warranties them that long and under proper storage they can last longer but at the same time I understand there is something of a static charge in parts of the mask that does the heavy lifting for particle trapping and that may dissipate over time or other materials may suffer degradation. I know it’s important to keep them sealed in the wrapper packaging until time of use for instance.
The things to look for as I understand are: they don’t smell strongly off when opened (outside of packaging smelling doesn’t matter), the adhesives aren’t breaking down (nose pads coming off, melting), the straps don’t snap on first use (probably least consequential but it could be a sign of bad storage conditions and stresses to the rubber/elastic and hence the rest of it) and they fit test properly. The straps on these ones aren’t that great anyways, I’ve had store bought ones of this model break on me after the first use if I pulled a little too far trying to get them out and over my hair without tangles.
5 year rating is based on NIOSH and the 3m warranty. During 2020 there was some papers put out by NIOSH regarding using beyond their expiration date (due to shortages) and it’s the usual about watching for straps and cushioning to fail first. No real way to check the electrostatic filter without a proper tester I guess. Idk if the fit test technique would be as useful?
Which material would be the first to fail? The elastic?
Most pharmaceuticals are shelf stable for a human lifetime, but there is little incentive to do the validation testing to prove it. I suspect masks are similar.
Edit: Never mind, I see you already said the same thing.
In my experience with this (type) of mask the elastic does fail first after a few reuses. But I can’t say definitively that the mask itself wasn’t compromised before that as I have no way to scientifically test it. Sometimes I get discoloration on the inside too maybe from my skincare products or something which probably doesn’t impact function but does make them a little gross seeming to rewear after that.
If you replaced the elastic on these you could maintain a good seal through many re-uses but I understand the filtering doesn’t last forever. I’ve seen people on reddit say I think 40 total hours absolute max wear-time and that’s assuming multiple rest periods in a paper bag for several days or a week between like 4-5 wears I think of maybe 8 hours max each. I am pretty sure that liquids compromise the filtering. So if you enter an area with misters/mist or very high humidity or get water all over them that compromises the filtering I believe and is cause to discard.