Cov khoom noj khoom haus yog lub ntim ntim kaw uas muaj peev xwm sib txuas ntawm cov khoom noj, thiab cov khoom noj khoom haus yog qhov tseem ceeb ntawm lub cev, thiab cov khoom noj khoom haus yog ib qho khoom noj khoom haus, tuaj yeem npog gasket thiab lwm yam {2} {2} {2} {2} {2}.
