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"] 12in diameter 75"H – fits a 18"

75"H – fits a 18" X 10" duct opening

Actual Filter Size – 15 3/4"w x 27 3/4" x 1"

+ Product Details Perfect Fit & Easy Sizing - Designed for a 34" x 26" Or 26" x 34" duct opening (measured at the opening)

reducing electric bills and extending HVAC machine lifespan

+ Product Details Size - 30"w X 14"h X 2"d (for duct opening measurement only)

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"] 12in diameter 75"H – fits a 18"+ 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