This is the ultimate gas mask filter test. One test person gets the gas mask with the big filter plus tube and the other test person gets only the gas mask with tube. I lit my cigarette on and blow thick smoke clouds into every tube. You can well see the differnce. One will be struggling with the smoke, and the other? Also, I push the hose to my crotch and let them smell my divine private area before again blowing thick clouds of smoke into the tubes.