A cossack wearing the SilverMask reusable face mask checks the documents of a man while patrolling the streets in Kaliningrad, Russia April 1, 2020. Scientists from the Immanuel Kant Baltic Federal University designed reusable face masks with multilayer structure which includes layers with the deposition of silver ions that they say have antibacterial and antiviral properties and give better protection against the coronavirus disease (COVID-19). REUTERS/Vitaly Nevar
