32"W X 4"H [Duct Opening] Steel Air Vent Return Grille - HVAC VENT DUCT COVER DIFFUSER - [Outer Dimensions: 33.75"W X 5.75"H] w36h36 Complies with industry standards of 4 X 12 Is CRFG2028 Width_14in

Complies with industry standards of USA: ASTM D-882

Energy Efficient – Air-tight inner core decreases the pressure loss and provides a more hygienic environment - high energy efficient / No fiberglass erosion into air stream

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+ Product Details Size - 12"w X 32"h is the size for the duct opening measurement only

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

32"W X 4"H [Duct Opening] Steel Air Vent Return Grille HVAC VENT DUCT COVER DIFFUSER [Outer Dimensions: 33.75"W X 5.75"H] w36h36 Complies with industry standards of 4 X 12 Is CRFG2028 Width_14in Complies with industry standards of USA: ASTM D 882 Energy Efficient – Air tight inner core decreases the pressure loss and provides a more hygienic environment high energy efficient No fiberglass erosion into air stream