14"
x 14" Duct Hole [15.6" x 15.6" Face] Aluminum 4-Way Vent Cover:
Adjustable Curved Blade Air Supply Diffuser - Plastic Seal for Tight
Fit, Quiet Air Flow, Multi-Shutter Damper
[Quadruple Curved Blade Airflow Control]:
Front blades shape the airflow in four directions 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.