20"W X 4"H [Duct Opening] Linear Aluminum Clip-On Bar Return Air Grille [Outer Dimensions: 21.25"W x 5.25"H] Insulated Flexible Ducts R-6.0 + Product Details Size -

+ Product Details Size - 6"w X 36"h is the size for the duct opening measurement only

1/2" - 3119 PSI

+ Product Description Maximize the efficiency of your ventilation system with our top-of-the-line HVAC grilles and registers

+ Product Details Size - 28"W X 6"H is (for duct opening measurement only)

20"W X 4"H [Duct Opening] Linear Aluminum Clip-On Bar Return Air Grille [Outer Dimensions: 21.25"W x 5.25"H] Insulated Flexible Ducts R-6.0 + 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