The outer layer of the mask tends to accumulate a lot of dirt in the outside air, such as dust and bacteria, and the inner layer is blocking the bacteria and saliva that exhale, therefore, both sides cannot be used alternately, otherwise the contaminated outer layer will be inhaled into the...https://www.rollmed.net/face-mask/oxygen-c-mask.html
Oxygen C Mask
Spedito - 26/11/2020 : 17:10:56
