20"w X 20"h Extruded Aluminum Adjustable Core Mount Supply Ceiling HVAC Air Grille – Interchangeable: 1-Way, 2-Way, 3-Way or 4-Way - Vent Duct Cover [Outer Dimensions: 21.125" X 21.125"] w24h24 and its seamless drop-in installation

and its seamless drop-in installation process ensures effortless setup

Ideal for Walls & Ceilings: Designed for seamless installation in standard 16" X 4" duct openings

Round-neck-to-square-face construction results in 360 degree air diffusion pattern similar to a full round diffuser

Actual Filter Size – 11 3/4"w x 5 3/4" x 1"

actual front end outer dimensions are approximately 22 5/8" width X 8 5/8" height

20"w X 20"h Extruded Aluminum Adjustable Core Mount Supply Ceiling HVAC Air Grille – Interchangeable: 1-Way, 2-Way, 3-Way or 4-Way - Vent Duct Cover [Outer Dimensions: 21.125" X 21.125"] w24h24 and its seamless drop-in installation+ Product Details Size 20"w X 20"h Is The Size For The Duct Opening Only, Dimensions With Outer End are 21. 125" X 21. 125". Design Re configurable Interchangeable Sections Easily convertible into 1 Way, 2 Way, 3 Way, or 4 Way Just lift sections and rotate to re configure direction. High Quality Aluminum The premium durable aluminum will never rust and it will never wear through leaving the material with an elegant, beautiful, and smooth surface, adds