Mask Fitters for FFP2/KN95 Masks

The recent shipment of FFP2 masks to Belgium have been found to provide insufficient protection for the wearer, despite having fully functional filters. Due to their loose fit, they allow leaks that undermine the effectiveness of the mask. 

We have been working together with the Belgian government and a number of hospital experts, including UZ Gasthuisberg prevention advisor Herman Devriese, to develop a solution which will allow the unusable KN95 masks to be worn safely.

The Materialise Mask Fitter is a reusable and easily implementable accessory that provides a good face fit without leaks – it goes over the mask and is fixed in place with elastic straps. For instructions on how to choose the right size and wear your FFP2 mask with the Mask Fitter, please watch this video, or read the instructions.

Contact us

A well-fitted mask can be slightly more difficult to breathe through, but this is also a sign that the mask works well and is fully protecting its wearer.

This product comes in four sizes: Small, Medium, Large, and Extra Large. It will be sent along with buttonhole elastic straps that will allow you to attach the Mask Fitter to the mask. Please ensure you choose the correct size or the Mask Fitter will not function properly. The sample set can be a valuable tool in ensuring you have the correct sizes; from experience we have found that 80% of users will need Small or Medium, 15% will require a Large and 5% will require an Extra Large Mask Fitter.


The Mask Fitter is only an accessory which can be used together with a PPE mask. We do not claim for it to be, nor should it be used as, a medical device. Therefore the Mask Fitter is also not required to comply with PPE standards (Personal Protective Equipment).

Please use standard cleaning procedures relevant to your institution when re-using the mask fitters.

We have applied for design protection for this model (it is prohibited to copy this product). 
The Mask Fitter was based on an initial design by Mark Fuller.

Materialise is currently working on many other solutions to help the fight against COVID-19, including a 3D-printed non-invasive PEEP mask, hands-free door opener and flexible software licenses.

Learn more about our other initiatives.

Find out more