4" x 12" Duct Hole [5.6" 13.6" Face] Aluminum 1-Way Vent Cover: Adjustable Curved Blade Air Supply Diffuser - Plastic Seal for Tight Fit, Quiet Flow, Multi-Shutter Damper

[Proper Sizing First]: Measure your ceiling opening at exactly 4" x 12" before purchasing. The visible face measures 5.6" x 13.6", ensuring a perfect fit and smooth finish after installation. [Easy Installation]: Installs easily on ceilings, drop ceiling panels, or drywall. Ideal for both domestic and commercial applications, serving as the perfect ceiling diffuser or ceiling vent cover. [Screws Included]: Comes with galvanized steel cross-head screws (5/32" diameter x 1 1/2" length, white head) designed for wood and drywall. Suitable for heater vent covers or heat vent covers. [Not For Floor or Exterior Use]: Specifically designed for indoor ceiling applications only. Not intended for flooring or outdoor installations. [Semi-Matte White Finish]: Features a semi-matte Laminaire W finish (similar to RAL 9003), ensuring a modern, subtle aesthetic that complements any interior décor. [Lightweight Design]: The diffuser’s lightweight construction prevents it from sagging or becoming dislodged over time, maintaining a secure and stable fit. [Rubber Gasket Included]: A rubber gasket lines the perimeter of the hollow, preventing air leaks and optimizing HVAC system efficiency. [Reinforced Corners]: Internal reinforcements behind the unions prevent the corners from separating, ensuring long-term structural integrity. [Curved Blade Airflow Control]: Front blades shape the airflow and should never be fully closed. For lower ceilings (up to ~12ft), set up to 45°; for higher ceilings, open beyond 45° for broader air diffusion. [Damper for Air Volume Only]: The damper controls air volume, not direction. Open it fully and gradually close until achieving the desired airflow, ensuring comfort without altering air direction.