The Reinier de Graaf hospital in Delft, Netherlands, has submitted a design for FFP2 masks to the Dutch government. Masks made according to this design, optimally protect healthcare professionals against infection with the coronavirus. With this design, mass production can be set up, to overcome the acute shortage of safe mouth masks for healthcare employees in the Netherlands. The mouth masks were developed by a task force from the Reinier de Graaf hospital, TU Delft and the fine chemical company DSM. They have been tested by TNO and meet all safety requirements of an FFP2 mouth mask.