I measured the Shadow Moon KF94 3 times above. Is legit results....at somewhat high ambient levels to stress test the mask. Else with ambient of 2-3k, even 5k, is not enough for all these very high filtration masks.
In fact, 14-16k particles/L @ 0.5 microns levels still not that sufficient for these masks, really need double that, preferably above 30k.
It's quite impressive. Able to hang around with the Good Manner, Bluna white and Bluna black.
Chamsarang is also good. F731 K-medic and Doctor P&B are very decent as well.
That time just before F919 came out, was intending to get this. Coz the packaging of the woman, like quite.....i mean, my wife likes it.

Can use $3 coupon. Not sure if can use free ship coupon simultaneously with a trick at $14.90 price.
From here
Incredible shopping paradise! Newest products, latest trends and bestselling items、[KOREA No.1 KF94 Mask] Sol+ 50PCS KF94 KFDA Certified / Individual Packaging / Made in KOREA:Small Appliances, Items from Singapore, Japan, Korea, US and all over the world at highly discounted price!
www.qoo10.sg
Page 4 and beyond
Read quite a number of people kaobei kaobu that they did not receive real KF94s, not SOL etc.

But now cannot get liao.
F919 Chamsarang is also rather good, but 没有了 。
Oct 19, 2021
Written by blu***(SG
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Ordered on 7th received on 19th nov. If you need them urgently then need to purchase it elsewhere. Item receive in good condition. Thanks seller
MODEL:KF94 50PCS
Oct 19, 2021
Written by civ***(SG
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Can't tell if it I'd KFDA certified as there no indicator and the brand I received is shadow moon