12" X 6" [Duct Opening] 1-Way Air Vent Adjustable Aluminum Curved Blades Integral Multi-Shutter Damper HVAC Diffuser [Outer Dimensions: 13.75"W X 7.75"H] Color_Black Actual Filter Size – 21

Actual Filter Size – 21 3/4"w x 17 3/4" x 1"

Insulation density is 30kgs/cbm = 0

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

actual front end outer dimensions are approximately 27 5/8" width X 16 5/8" height

Actual Filter Size – 7 3/4"w x 17 3/4" x 1"

12" X 6" [Duct Opening] 1-Way Air Vent Adjustable Aluminum Curved Blades Integral Multi-Shutter Damper HVAC Diffuser [Outer Dimensions: 13.75"W X 7.75"H] Color_Black Actual Filter Size – 21+ Product Details Size 12"w X 6"h is the size for the duct opening measurement only, actual front end outer dimensions are 13. 75" width X 7. 75" height. Design Individually adjusting curved blades. Multi shutter damper with handle operator to adjust air flow. Screws Included High Quality Aluminum The premium durable aluminum will never rust and it will never wear through leaving the material with an elegant, beautiful, and smooth surface, adds a