12" X 20" ALUMINUM RETURN FILTER GRILLE FOR 1" FILTER - EASY AIRFLOW - LINEAR BAR GRILLES 16" Round Duct Pipe then you'll need a 14-inch

then you'll need a 14-inch round vent

Actual Filter Size – 19 3/4"w x 17 3/4" x 1"

actual front end outer dimensions are approximately 28 5/8" width X 32 5/8" height

With a 4" diameter for the duct opening measurement

Quality Packaging – Every part is hand inspected for quality before it is packaged

12" X 20" ALUMINUM RETURN FILTER GRILLE FOR 1" FILTER - EASY AIRFLOW - LINEAR BAR GRILLES 16" Round Duct Pipe then you'll need a 14-inch+ Product Details Size 12"w X 20"h is the size for the duct opening measurement only, [Outer Dimensions: 14. 5"w X 22. 5"h] Actual Filter Size 11 3 4"w x 19 3 4" x 1" High Quality High quality rust free, strong aluminum construction with smooth finished edges for easy and safe use; Filter grille features a user friendly plastic latch that requires no screwdriver for opening. Installation Location Sidewall and ceiling. Design Heavier gauge than needed,