The Lambro 4 In. black ABS plastic exhaust roof vent with a molded 1.5 In. collar is ideal for venting through the roof. This vent is used for clothes dryer exhaust, bath fan exhaust and other general venting applications that require moist air and humidity from exiting the home. The redesigned damper allows for maximum airflow while reducing back flow of exhaust air. WARNING: This roof vent can ONLY be used for shingled roof installations. NOTE: Clothes dryer exhaust installation requires the plastic screen to be removed and the screen holder tab to be trimmed off with a utility knife.