Frequently Asked Questions: Filti Filter and Canada Strong Cotton Face Mask

How Does Filti Nonwoven Polypropylene + Nanofiber Filter Material Compare to Other Filter Materials?

This independent US researcher tested Filti against dozens of other mask filter materials on the industry standard TSI 8130 machine at 0.3 microns. This is the same test protocol used for N95 mask material. Filti came out on top, with excellent filtration and high breathability! See more at


Aren't Viruses are Smaller than 0.3 Microns?

A dried SARS-CoV-2 coronavirus is approximately 0.125 microns in size. Filti does have some filtering ability in this range. However the majority of airborne virus particles are rarely floating around naked. Instead, they are most often bonded to water droplets with size 0.3 to 5.0 microns - a range where Filti has high filtration efficiency.

It is important to note that Filti is not a guarantee to prevent COVID-19 especially in acute exposure situations. When using Filti it remains important to maintain a tight leak-free mask seal, to minimize exposure to shared airspaces, to practice social distancing, to consider eye protection, and to maintain proper hand hygiene.

What are Filti Filters Made Of?

Filti is made of a three-layer composite construction with patent-pending nanofiber:

  • Spunbond Polypropylene Non-woven (face inward)
  • Ultra-thin proprietary nanofiber filter membrane
  • Spunlace Polyester (face outwards)

How is a Filti filter used?

Filti filters are suitable to use ideally with a cloth mask that has a pocket insert for filters.  Simply insert the filter in the inner pocket of your cloth mask.

how to insert filti filter non-woven polypropylene spunbond meltblown into face mask

Which Side of the Filter goes Out?

Position the fuzzy side outwards, and the smoother silky side towards your face.

How Long Can I Wear the Mask and Filti Filter?

To avoid buildup of micro-organisms from moist breath, dispose of the filter and wash the mask with laundry soap and warm water every 8 hours of use (e.g. 8 x 1-hr shopping trips or 1 x 8 hr work day). Hang-dry the mask for best results. Machine-drying may cause shrinkage of this 100% cotton product. Once dry, insert a new filter. 

Can I Wash a Filti Filter?

Please no! Nonwoven filters from any manufacturer should never be washed because doing so degrades filter performance. Washing displaces the nonwoven fibers, leaving holes which reduce filtration effectiveness. It may also alter any static filtration performance. For these same reasons N95 and FFP-2 masks in a medical setting are never washed.

Do you have a Child Face Mask Filter?

Our Filti filter inserts fit most masks for youth 11+. For smaller masks, the Filti material can be easily trimmed with scissors.

Where Can I Get Filti Filters for a Face Mask?

Canada Strong Masks sells filti filter inserts for face masks in a convenient 10-pack at this link 

Do You Sell Masks and Filters in Bulk?

Yes we do! Please check out our Bulk Products. Or contact us for higher quantities:


Do Masks and Filters Work?

Nothing is 100% effective, but tightly-fitting masks and effective filters may reduce the potential for respiratory transmission.