Don't just that, the vent carries this moist air from the dryer to the house's exterior. Within the again of every dryer is often a 4-inch diameter metallic vent that expels the water-laden air.Whirlpool 4396037RP Vent Periscope See It When there isn’t ample clearance guiding your clothing dryer to support a four-inch dryer tube, a periscope vent