Round Stack Boot 12" X 3.25" X 6"- is Compatible with Duct 6" Height_14in + Product Details Size - actual front end outer RFG1818 Black Welding & Soldering

+ Product Details Size - 18"w X 28"h is the size for the duct opening measurement only

+ Product Details Size - 30"w X 10"h is the size for the duct opening measurement only

Actual Filter Size – 35 3/4"w x 5 3/4" x 1"

+ Product Details Size - 30"w X 14"h is the size for the duct opening measurement only

If you are looking to enhance your project with a top-of-the-line unit

Round Stack Boot 12" X 3.25" X 6" is Compatible with Duct 6" Height_14in + Product Details Size actual front end outer RFG1818 Black Welding & Soldering + Product Details Size 18"w X 28"h is the size for the duct opening measurement only + Product Details Size 30"w X 10"h is the size for the duct opening measurement only