30" X 24" Steel Return Air Filter Grille for 1" Filter - Removable Frame - [Outer Dimensions: 32 5/8" X 26 5/8"] w16h16 Adjustable airflow control - by

Adjustable airflow control - by rotating the middle disk

actual front end outer dimensions are approximately 15

actual front end outer dimensions are approximately 18 5/8" width X 30 5/8" height

1/2" White insulation will give you a good R value of 3

30" X 24" Steel Return Air Filter Grille for 1" Filter - Removable Frame - [Outer Dimensions: 32 5/8" X 26 5/8"] w16h16 Adjustable airflow control - by+ Product Details Size 30"w X 24"h is the size for the duct opening measurement only, actual front end outer dimensions are approximately 32 5 8" width X 26 5 8" height Actual Filter Size 29 3 4"w x 23 3 4" x 1" High Quality High quality solid stamped steel with counter sunk screw holes (screws included) and no sharp edges Installation Location Sidewall and ceiling Design Removable door face for easy filter change & cleaning uses a 1" thick filter.