18" X 8" Steel Return Air Filter Grille for 1" Filter - Removable Frame - [Outer Dimensions: 20 5/8" X 10 5/8"] w10h10 actual front end outer dimensions Product Details Perfect Fit SV2414 HP 12" Round Duct Pipe

actual front end outer dimensions are 19" Width X 13" Height

actual front end outer dimensions are approximately 10 5/8" width X 12 5/8" height

actual front end outer dimensions are approximately 18 5/8" width X 24 5/8" height

providing efficient performance of up to 300m3/h

+ Product Details Size - 40"w X 20"h is the size for the duct opening measurement only

18" X 8" Steel Return Air Filter Grille for 1" Filter Removable Frame [Outer Dimensions: 20 5 8" X 10 5 8"] w10h10 actual front end outer dimensions Product Details Perfect Fit SV2414 HP 12" Round Duct Pipe actual front end outer dimensions are 19" Width X 13" Height actual front end outer dimensions are approximately 10 5 8" width X 12 5 8" height