20"w X 20"h Extruded Aluminum Adjustable Surface 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"] 3-Way or 4-Way this flex duct decreases the

this flex duct decreases the pressure loss and provides a more hygienic environment

actual front end outer dimensions are approximately 27 5/8" width X 12 5/8" height

4" X 14" Is The Size For The Duct Opening (floor/vent hole) Measurement Only

+ Product Details Perfect Fit & Easy Sizing - Designed for a 10" x 28" or 28" x 10" duct opening (measured at the opening)

20"w X 20"h Extruded Aluminum Adjustable Surface 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"] 3-Way or 4-Way this flex duct decreases the+ 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