8" Inch Collar Duct Connector with Shutter for Flexible Aluminum Hose, Adjustable Flap, HVAC Ventilation Fitting, Easy Installation Aluminum Adjustable Curved Blade + Product Details Size -

+ Product Details Size - 4"w X 28"h is the size for the duct opening measurement only

+ Product Details 24" x 24" x 1" replacement air filters for your furnace

+ Product Details Size - 32"w X 18"h X 2"d (for duct opening measurement only)

These tabs dig into the main duct when you push the fitting in

+ Product Details Size – 28" x 30 or 30" x 28" is the size for the duct opening measurement only

8" Inch Collar Duct Connector with Shutter for Flexible Aluminum Hose, Adjustable Flap, HVAC Ventilation Fitting, Easy Installation Aluminum Adjustable Curved Blade + Product Details Size -Accordion Menu + Product Details Size Diameter Range: Available in a diameter range of 4" to 10", the Exiva Duct Collar can be used with a variety of duct sizes. Material Constructed from durable polypropylene, the Exiva Duct Collar is designed to withstand a wide range of temperatures and demanding conditions in HVAC systems. Design The collar features a smart, user friendly design that includes a flexible air duct connection, ensuring a tight fit