As you breathe through them, these respirators filter out contaminants in the air. Throw them out when soiled, damaged, or breathing is difficult.
N95 respirators filter out 95% of solid particles. They are not oil resistant.
Respirators with an exhale valve reduce breathing resistance and hot air buildup. They release your unfiltered breath out of the mask, so they are not for use in a medical setting.
Respirators with a mesh shell hold their shape in heat and humidity.
Respirators with a comfort strap unbuckle to let the mask hang loosely around your neck when not in use.