[EXCELLENT AIRFLOW]: roof vents with backdraft damper still have an airflow of UP TO 75%, while other products on the market have an airflow of less than 50% and poor ventilation. [HIGH-QUALITY ROOF VENT COVER]: roof vent for bath exhaust is constructed with heavy gauge steel durability and lasting use, has strong resistance. [EASY INSTALLATION]: 6 inch vent includes a pipe extension located underneath the flange for connecting to flex ducting, and there are four holes in the panel, which can help you install on the 4 inch bathroom exhaust fan roof jack more firmly. [REMOVABLE]: Removable panel for easier cleaning, roof dryer vent is designed for maximum airflow and protection, to be used with roof exhaust venting systems, can be used in conjunction with 6 inch duct and exhaust fans for house ventilation. Colour:As Shown Material:Plastic Package Contents: 24x Edge brush Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.