16" x 12" Cube Core Eggcrate Return Air Filter Grille for 1" Filter steel + Product Details Size – Compatible With Duct 7in Applications This sheet metal DDAG-A-1212

+ Product Details Size – 32"w X 34"h is the size for the duct opening measurement only

And The Cooler Air From Outside WIll Flow In From The Bottom

with actual outer dimensions of 8

+ Product Details Size – 32"w X 18"h is the size for the duct opening measurement only

+ Product Details Perfect Fit & Easy Sizing - Designed for a 18" x 32" OR 32" x 18" duct opening (measured at the opening)

16" x 12" Cube Core Eggcrate Return Air Filter Grille for 1" Filter steel + Product Details Size – Compatible With Duct 7in Applications This sheet metal DDAG A 1212 + Product Details Size – 32"w X 34"h is the size for the duct opening measurement only And The Cooler Air From Outside WIll Flow In From The Bottom