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 Actual Filter Size – 9

Actual Filter Size – 9 3/4"w x 25 3/4" x 1"

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

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

+ Product Details Perfect Fit & Easy Sizing - Designed for a 34" x 16" Or 16" x 34" duct opening (measured at the opening)

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 Actual Filter Size – 9+ 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