10" X 18" Steel Return Air Filter Grille for 1" Filter - Removable Frame - [Outer Dimensions: 12 5/8" X 20 5/8"] Fixed Blades with Damper + Product Details Size – 4 X 12 Is CRFG2028 Width_14in

+ Product Details Size – 18"w X 34"h is the size for the duct opening measurement only

2" X 10" Brass Victorian Floor Register Grille - Modern Contempo Decorative Grate - HVAC Vent Duct Cover - Brass Plated

+ Product Details Size – 6"w X 14"h is the size for the duct opening measurement only

+ Product Details Size – 10"w X 28"h is the size for the duct opening measurement only

actual front end outer dimensions are 15

10" X 18" Steel Return Air Filter Grille for 1" Filter Removable Frame [Outer Dimensions: 12 5 8" X 20 5 8"] Fixed Blades with Damper + Product Details Size – 4 X 12 Is CRFG2028 Width_14in + Product Details Size – 18"w X 34"h is the size for the duct opening measurement only 2" X 10" Brass Victorian Floor Register Grille Modern Contempo Decorative Grate HVAC Vent Duct Cover Brass Plated