do you mean if you cough or something?
there is a valve on the mask so you can exhale without breathing out of the entrance of the mask.

the whole thing works like a charm, you just breath, get light headed and reallly baked
nikweiser Reviewed by nikweiser on . GASMASK! im so high:S2: :S2: :S2: :S2: i passed out from hitting it in the chair and my eyes are so teared up :S2: :S2: :S2: :S2: :S2: IM SO HIGH i forgot to put the picture lol it gets your retarded lol were SO BAKED Rating: 5