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Flo Mask Test Reports

Because your trust is so important to us, we feel it's critical to be transparent with our test reports by making it publicly available.

The following reports prove that Flo Mask performs at the highest levels, as tested by renowned laboratory institutions in the USA and abroad. And unlike other elastomeric mask companies, we make it a point to test our masks as a complete system, not just the filter.

Flo Mask Pro KN95 Test Report (PDF)

NIOSH Test Report (Mask Challenge)

 Additional Independent Test Reports


Frequently Asked Questions

Q. Is Flo Mask KN95 certified?

The simple answer is yes for our adult mask, but not for our kids' mask.

Our adult mask (both sizes) has been fully tested and received KN95 certification for our Pro and Everyday Filters. Furthermore, as a participant in the Mask Challenge, NIOSH independently tested our Pro Filter to achieve over 99% filtration efficiency while our Everyday Filter achieves over 95%.

The filter media on our kids' masks were specially designed for little lungs to maximize breathability while maintain high filtration efficiency. Holding our kids' filter to adult test standards made no sense. But when adjusting the flow rate at 6.3 LPM to better match normal respiratory rates of most children, Flo Mask for kids achieved over 95% filtration efficiency.

Independent test reports for kids and adult masks can be found in the links above


Q. I live in Europe, can I get a mask?

Unfortunately we're not shipping masks to Europe at the moment. We're in the process of applying for CE approval by testing against FFP2 standards. Our goal is to complete this by early 2023.

If you already own a mask and need to replenish your filters or accessories, please contact our customer service team at so we can help you.


Q. Will Flo Mask fit me and my child?

Kids' mask recommended for 4 to 12 years of age. 

Fit was our core pillar from day one. That's why our team invested heavily in utilizing the very best 3D scanning technology to scan elementary aged kids across various ethnicities. As a result, we believe we've created an optimal fit for most kids ages 4 to 12. Our incredibly soft silicone gasket has been engineered to flex and accommodate various face shapes and sizes among this age group. 

Under 4 years of age. 

Although our mask wasn’t designed for kids younger than 4, we’ve had many parents use Flo Mask on kids as young as 2 and the feedback we’ve received is that it fits quite nicely. However, this is a decision a parent must make. To better help you make this decision, our mask dimensions (measuring inside dims from silicone gasket to silicone gasket) are:

Height (nose to chin): 60mm 

Width (sides of mouth): 64mm 


Two nose bridge sizes for adults.

Our adult mask was designed as a one size fits most with just a single difference, the nose bridge size, which we offer in two sizes: low/med and med/high. Based on our data, it should fit over 90% of the world's adult population.

Use our nose bridge print out tool here (to ensure accurate scaling, please print directly from Adobe Acrobat).

Here are our mask dimensions (measuring inside dims from silicone gasket to silicone gasket).

Height (nose to chin): 77mm 

Width (sides of mouth): 86mm 


Q. How often should I change the filter?

Based on our load testing data, we recommend the following assuming an AQI of 100 or less (average air quality index in Shanghai):

  • Kid Filter - Up to 8 hours of use
  • Pro Filter - Up to 40 hours of use
  • Everyday Filter - Up to 20 hours of use

Replace more frequently in poor air quality environments.

Fresh filters help maintain good breathability and when not in use, please store the mask in the included microfiber pouch as the filters are electrostatically charged and will continue to attract particulates in the air if left sitting out.


Q. Does Flo Mask have an exhaust valve?

Flo Mask does NOT have an exhaust valve. We found that the high breathability of our filters reduced the need for an exhaust valve.


Q. Is the filter recyclable?

Unfortunately, the unique material and manufacturing process to create our filters does not allow it to be recyclable. Please properly dispose of the filter in the trash and remember to always wash your hands with soap after handling a used filter.


Q. Can I use Flo Mask or Flo Mask Pro for an MRI? 

The primary housing of Flo Mask and Flo Mask Pro are made of polycarbonate and silicone, which do not have any metal in them. However, the straps do contain metal in the buckle and push button lock. Therefore, if you're looking to use Flo Mask or Flo Mask Pro for an MRI, please be sure to replace both straps with your own pure elastic ones. 


Q. Does Flo Mask contain latex rubber? 

Our elastic straps currently use latex rubber. We're in the process of transitioning all masks away from the latex straps to our new latex-free straps which we're also offering as a separate item.


Q. Where is Flo Mask made?

One of the most important aspects of Flo Mask, the filter, is manufactured here in the United States. The mask itself is manufactured in China through a highly reputable manufacturer that makes products for some of the most notable brands in the world. All packaging is printed in California and we perform the final assembly here in the San Francisco Bay Area to ship out to you.