The Airinum Urban Air Mask has 2 exhalation valves which act as ventilation systems for the mask - Removing moisture, heat and carbon dioxide to make the mask easier to breathe through. When you breathe, the valves are transporting out the exhaled air to prevent the mask from becoming warm and moisty. The valves are engineered to only transport out the exhaled air, and not let any unfiltered air to sneak in. 

The Exhalation Valve Stoppers are optional to use and can replace the Valve Caps on the Urban Air Mask 2.0. The Exhalation Valve Stoppers should be used when you want to plug the ventilation function of the mask. 

The Exhalation Valve Stoppers have been tested at RISE R&D Center in Sweden with evidence showing that it will block 99% of the exhaled air, diminishing the risk of respiratory droplets escaping into the ambient air.

The Exhalation Valve Stoppers are attached to the valves in the same manner as the Valve Caps. The difference between the two is:

(1) The Exhalation Valve Stoppers have an additional ring inside which closes the blue silicone disc on the valve and thereby disables the ventilation function.  

(2) The print on the outside of the Exhalation Valve Stopper indicates that the valve function has been disabled.

How to attach the Exhalation Valve Stoppers: