36" X 16" Steel Return Air Filter Grille for 1" Filter - Fixed Hinged - [Outer Dimensions: 38 5/8" X 18 5/8"] w6h6 + Product Details Size – Drop Ceilings / Aluminum The set includes a FG1836 HP-1

+ Product Details Size – 18"w X 12"h is the size for the duct opening measurement only

actual front end outer dimensions are approximately 13

+ Product Details High Quality - Aluminum housing on the outside and on the inside for the best insulation value

Great emphasis has been invested in the design of this product to prevent it from kinking in sharp bends & turns and to hold steady and at full diameter in all applications

Scratch-Resistant Finish - The powder-coated surface offers a smooth

36" X 16" Steel Return Air Filter Grille for 1" Filter Fixed Hinged [Outer Dimensions: 38 5 8" X 18 5 8"] w6h6 + Product Details Size – Drop Ceilings Aluminum The set includes a FG1836 HP 1 + Product Details Size – 18"w X 12"h is the size for the duct opening measurement only actual front end outer dimensions are approximately 13