12" x 28" or 28" x 12" Cube Core Eggcrate Return Air Grille w16h16 + Product Details Size -

+ Product Details Size - 36"w X 28"h is the size for the duct opening measurement only

Actual Filter Size – 19 3/4"w x 23 3/4" x 1"

Actual Filter Size – 33 3/4"w x 19 3/4" x 1"

Easy Unrestricted Air Flow For Your HVAC System

actual front end outer dimensions are approximately 20 5/8" width X 338 5/8" height

12" x 28" or 28" x 12" Cube Core Eggcrate Return Air Grille w16h16 + Product Details Size -+ Product Details Size 12" x 28" or 28" x 12" is the size for the duct opening measurement only, actual front end outer dimensions are approximately 13. 75" X 29. 75". High Quality High quality, rust free aluminum construction with smooth finished edges and counter sunk screw holes (screws included); no sharp edges.. Installation Location sidewall and ceiling. Design Cubic core eggcrate design Offers highest airflow efficiency at almost 95%, reducing