Product Design: The 4 inch white RAL9016 round diffuser valve mainly includes the outer ring, the inner ring, the screw and the beam. The gap can expand and contract to meet your ventilation needs by rotating the disc Premium Quality: The vent cover surface will be nonyellowing and the steel sheet material is very sturdy and durable. The AC vent cover adopts spraying and galvanizing processes to enhance rust resistance Easy Installation: The vent can be installed on ceilings and walls. You can fasten it with screws optionally and adjust air flow with a simple rotation to enjoy a comfortable room environment Extensive Application: The ceiling vent cover is generally used for office, bathroom, washroom, bedroom, kitchen and other indoor small space ventilation. The air vent design allows airflow to pass through the room ventilation more efficiently Warm Prompt: Please note the diameter of this air vent is 3.8" and it can be fit in a 4" diameter pipe or hole easily. If you have any questions about our air vent cover, our professional customer service team is here to assist you Transform your living space into a comfortable haven with our AC round vent deflector—the great solution for optimizing your airflow and enhancing HVAC efficiency. Designed with precision and durability in mind, this adjustable vent diffuser fits standard vent duct sizes, including 4-inch and 6-inch vent cover ducts. Perfect for both home and office use, our ceiling vent deflector maximizes the performance of your HVAC system while minimizing energy consumption. Ideal for ceiling air vents or wall air vents in communal areas, like bathrooms, washrooms, bedrooms, kitchens, offices, hotels and so on. Experience easy installation and transform how comfortably you live indoors!