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" but you’ll appreciate the benefits

but you’ll appreciate the benefits over a long period of time

+ Product Details Size - 30"w X 36"h is the size for the duct opening measurement only

Optimal Airflow: Experience 25% greater airflow

Actual Filter Size – 31 3/4"w x 27 3/4" x 1"

+ Product Details Size - 30"w X 6"h is the size for the 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] Compatible with Duct 10" but you’ll appreciate the benefits+ 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