12" x 12" - Corner Direction Extruded Aluminum Ceiling Diffuser Square - HVAC Vent Cover Powder-Coat Finish - Smooth, Shiny, Scratch-Resistant, Beautiful. Looks Like It Was Just Waxed Quality Packaging - Carefully Shrink Wrapped with Cardboard Backing to Prevent Damage in Shipment Smooth Surface Edges - Run Your Fingers Across The Surface To Feel The Smoothness Screws Included - Easy Unrestricted Air Flow For Your HVAC System 12" x 12" - opening (vent hole - Neck Size) dimension - actual size is approx 2" wider