Merv 16 Polypropylene Material (30 Square Feet) for DIY Mask Inserts and Projects,Electrostatic Filter Material 99 percent Efficient at 0.3 um,Non-woven Fabric 24” x 180” Cut to Any Size

The testing stats are printed right on the package and match the sellers description and the seller sends a 'suggested use' email I found helpful as well as their answers to questions above.This fabric seems to surpass the filtering capacity of the available masks today, but only good design and fit will yield optimal filtering results. You must breathe 'through' the filter for it to work, not around it.After buying and sewing many different versions of masks I realized you need a filter; fabric alone doesn't cut it. The electrostatic charge of this wonderful filter fabric makes it hard to insert into a replaceable filter mask, plus there's a bit of leakage around the perimeter of the filter in that type of design.So, I settled on a throw-away 3-piece, sewn together mask with this filter as the inner layer. (Lot's of fabric on hand. let's use it...)All three layers - the outside fabric, inner face liner fabric and filter fabric - are cut from the same full-size pattern and cover the entire face.Filter and inner face liner are sewn together along the center-line and the seam-line sealed.Then sew the face fabric to the filter/inner face liner pieces.Turn it right-side-out, add stiff nose wire, sew the perimeter, add 5/16" elastic head-loops and nose foam.Best mask out there.I cannot smell bacon cooking nor the dog run when I'm wearing it :)I've been using 3M 8210 for thirty years as a woodworker and cannot get them now. All other mask designs I get wood dust in my nose yielding a fail.With my 3 layer masks I'm getting even better results the the 3M (according to my nose).Note: some of the 'better' fabrics out there are very fine woven and are a bit hard to breathe through. I rely on this filter material to do the job, not the fabric. Thinner 'cheaper' fabrics seem to work best. The fabric is in reality a pretty 'filter holder'. 100% cotton of course.The only reason I'd deduct a star - which I will not - is the fabric comes folded and the folds look pretty hard. I don't trust the folded parts as my filter. Consequentially, I cut them into the rectangles they were folded into. I get one mask per rectangle. Still a lot of masks however rolled material would be preferred as there would be less waste.In order to achieve the best fit, each member of the family has their own custom fit pattern and they are getting fine tuned as we go.Thank you for helping us stay safe with this killer Merv 16 filter material!!

This filters filtering abilities is the real deal. I live in a 748sft home with 2 children, 2 adults, 3 cats, a dog, and 2 gerbils. We have a lot going on in a small area and I take air quality among other things very serious in our home. I use different sensors throughout the home to monitor the conditions. With that being said I have placed these filters over the merv13 filters to capture the ultra fine particles that pass through the merv 13 filters on all our air purifiers and furnace. After 3 weeks of I have started to see fine particles on one side of the and not on the back meaning that the filter was doing its job in capturing the particles and not allowing them to pass though. This is even true under closer inspection with a magnifine glass. This is great news compared to the other merve 16 filter that failed my inspection and was returned for particles passing through to the back side. This filter appears to be the real deal in being able to capture ultra fine particles of dust at least. I can't speak of its ability to capture viruses and such but can confidently say it captures ultra fine dust particles.

This is a very thin spun bonded plastic fiber. You can barely blow through it. It can be torn easily with your fingers. It is not suitable for cabin intake air filters on a vehicle. It would not work for air vent cover/filters in a building either - too much resistance to air flow. I really don't know what if would be useful for, it's so thin and easily torn and hard to get air through.In all fairness it is exactly as described and you do get a bunch of it for the money spent, I just ordered the wrong stuff for my application.

I cannot overstate the value for these filters. I have placed them on my air vents for my central cooling since my apartment smells since we moved in and they have caught an amazing amount of dust with and without a filter on the central cooling. I have also cut the filter from my roomba and super glued a cut out section of this filter where the previous filter paper was on the standard plastic roomba filter. I now have lots of roomba filter replacements that seem to work even better! A little goo-gone super glue remover and gorilla super glue and I can replace the filter anytime! I would especially recommend this for people with allergies. If this product is anywhere around $20 for 20x180" (the price I bought it for) it is an amazing deal. They require a significant amount of pressure to get good airflow but they are a very good filters otherwise.

I wanted to use it as a prefilter for an odd-size furnace return duct. It essentially completely blocks the air flow.I tried it on a standalone filter/fan to test - the Honeywell filter usually puts out enough flow to feel as a fresh breeze. With the fabric in place, the fan is struggling and only minimal air flows through; that is probably from leakage rather than what is (not) passing through the fabric.The Q&A answer that said "way too restrictive" is the one I should have paid attention to. I cut it, so I guess I won't try to return it. Perhaps I can find some use for it as a wind blocker... but it rips pretty easily so not sure what the heck I'll use it for.