4DflexiSPORT "Reusable Facemask, Respiratory Face Covering" review

Product https://www.4dflexisport.com/collections/face-masks/products/single-reusable-facemask-respiratory-face-covering-rfc-by-4dflexisport (UK retailer and manufacturer?)

The product is £15 ($19) and took a week to arrive by mail. It is advertised as:

".. proven scientifically to provide a significantly better barrier than the FFP2 face masks worn by [National Health Service] NHS staff". 

The following sentence says "FFP3 rating is frontline care". It is unclear whether that's a claim or a statement, which should be made clearer IMO.

Update: The study that the mask was featured in was about humidity at distance from the mask compared to other masks of known grade: https://www.tandfonline.com/doi/full/10.1080/03091902.2020.1797198

Anyway, the take away is this mask it really good I think. Super breathable. Especially when compared to the highest-spec mask I make (and use when out in public).

The fabric is double thickness with very fine stitching in the core places that air would filter in and out of the mask. 

Here I hold it to a ceiling light so you can see one spot where the fabric drops down to single thickness at the bridge of the nose (by the nose wire).  

I think that should be a little higher up the nose. Why? because air finds the easiest path and some small percentage of each inhalation of air is going to come through that 'easier' area than through the double thickness. Since the start of June, this has been eliminated in subsequent production runs  - I know because I've been mailed a second mask because of this review - fantastic job, gang!

This is an FFP2 mask though (I don't know if it is certified) though which means 94% filtration and an allowed 8% leakage.

The ear loops are clever as they have an attached strap for tying a bow behind your head. I have very short hair so this is not a problem for me. I find it preferable to have straps anyway, but with this mask they really help the ear loops stay around your ears without too much "pulling forward" pressure.

Comparing to my own (hoped for) FFP2 spec mask:

On the right - the mask I wear whenever I'm out in enclosed spaces in public. That's a RagMask Max. Six layers of satin from an Amazon bedding set, and one layer of 400-thread cotton outer. The number of layers in use bring that up to the FFP2 spec (calculated from the https://pubs.acs.org/doi/pdf/10.1021/acsnano.0c03252 study results).  

I had to add a plastic retainer to force cupping to increase breathability. The 

4DflexiSPORT mask I am reviewing here gets its cupping from simple fabric stiffness. and the fabric is more breathable too. It is much more breathable too. My lungs are strong enough to pull air though my less breathable mask for hours at a time, but everyone trying the two would see the difference and choose the 4DflexiSPORT over mine.

Comparing to my own (hoped for) FFP1 spec mask:

This is the "Fabric CT" mask that I blogged about previously. FFP1 is 80% filtration max allowed leakage 22% (whatever that means). Again this is calculated for me as I can't find any UK groups willing to fit test masks with a portacount machine.

The mask shown is two layers of satin and one layer of 180-thread cotton. It also has a retainer to force cupping. You can see I'm making the retainers slimmer now. Mine is still harder to breathe through than the higher-spec 4DflexiSPORT mask.

I've made the "fabric CT" mask with six layers of satin for a higher filtration spec, but there's less cupped fabric than the original Ragmask Max so it is harder to breathe through.

So in summary I think their mask is good. I hope it gets tested. If I could source their "Spacer Mesh Fabric", I might make designs based on that to give away rather than the ones I've been doing so far - but costs would go way up. I'd give mine to the NHS but they've not called - off topic perhaps. If the spec is correct, 4DflexiSPORT have an NHS grade respirator. At least for everyone not one foot away from a COVID-19 patient.

Disclosures: none. I bought mine from AngelMed, have received no money or other compensation for this review. I'm otherwise a competitor of theirs (even though I'm not selling mine).