Mask details

Sizes, Prices, Maintenance

A good fit is crucial

For the face masks to be effective, it is important that there is a good fit around the face. A mask which is too large will leave gaps for unfiltered air and particles to enter and leave. A mask which is too small will not stay in place correctly and thus be less effective



The mask's purpose is for the air to stream in and out through the cloth of the mask. THis ensures that the droplets which contain the corona virus adhere in the cloth and the optional KN95 filter. See here for a video by the Technical University of Delft which compares this effect for different types of masks. Type 3 in the video performs best and is the same design as offered by Duuja.


Our masks are produced with 100% Oekotex katoen and can be washed at 60 degrees. Longevity to save the environment and your wallet.


What does a package contain?

Package contents:

    • 1x face mask
    • 2x long cords
    • 2x cord stoppers
    • 1x KN95 filter
    • 2x Airbox
    • 1x manual

Our masks come in different sizes, so everyone can have a well fitting mask.

S size: for younger kids

M size: for women with a smallish face

L size: for women with a bigger face and men with a smallish face

XL size: for men with a full size face

To download and print a pdf with the mask in real size, please click on these links:

S in real size

M in real size

L in real size

XL in real size

When printing, please print with 'actual size' option enabled in the pdf printer.



Prices are as follows:

Cotton Face Mask: £12.90 (any size)

KN95 filter inserts (set of 10 pieces): £9.90

KN95 filter inserts (set of 20 pieces): £18.90


For the face masks to be effective, it is important that there is a good fit around the face


The FFP filter needs to be inserted carefully. See here for instruction.