20"W X 4"H [Duct Opening] Linear Aluminum Clip-On Bar Return Air Grille [Outer Dimensions: 21.25"W x 5.25"H] Compatible with Duct 10" + Product Details Size –

+ Product Details Size – 20" x 28" or 28" x 20" is the size for the duct opening measurement only

this stick-on collar with damper efficiently facilitates the delivery and removal of air

40" x 16" Aluminum Spiral Duct Air Vent Grille Cover - Fully Adjustable Double Deflection HVAC Air Supply

Screws Included - Easy Unrestricted Air Flow For Your HVAC System

High Strength - Closing Hatch Keeps it Locked In When Not in Use

20"W X 4"H [Duct Opening] Linear Aluminum Clip-On Bar Return Air Grille [Outer Dimensions: 21.25"W x 5.25"H] Compatible with Duct 10" + Product Details Size –+ Product Details Size 20"W X 4"H is (for duct opening measurement only); actual front end outer dimensions are 21. 25" Width X 5. 25" Height. Design Designed for concealed, flush placement on your wall with a 3 8 inch space between louvers, this linear grille comes with an installation frame and clips for easy hook in assembly, ensuring a refined and seamless look. High Quality Aluminum The premium durable aluminum will never rust and it will never