30" X 26" Steel Return Air Filter Grille for 1" Filter - Removable Frame - [Outer Dimensions: 32 5/8" X 28 5/8"] w25h25 Actual Filter Size – 15

Actual Filter Size – 15 3/4"w x 17 3/4" x 1"

The total outer size of this grille is the listed size plus plus 2 and 5/8"

Design – Cubic core eggcrate design Offers highest airflow efficiency at almost 95%

actual front end outer dimensions are approximately 27 5/8" width X 14 5/8" height

you can watch this informative video tutorial: How to Measure Your Vent Hole Before Ordering a Grille

30" X 26" Steel Return Air Filter Grille for 1" Filter - Removable Frame - [Outer Dimensions: 32 5/8" X 28 5/8"] w25h25 Actual Filter Size – 15+ Product Details Size 30"w X 26"h is the size for the duct opening measurement only, actual front end outer dimensions are approximately 32 5 8" width X 28 5 8" height Actual Filter Size 29 3 4"w x 25 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.