16" x 3" Aluminum Spiral Duct Air Vent Grille Cover - Fully Adjustable Double Deflection HVAC Air Supply [Outer Dimensions: 18w X 5"h] 6in diameter + Product Details Size –

+ Product Details Size – 12"w X 14"h is the size for the duct opening measurement only

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Actual Filter Size – 24 3/4"w x 35 3/4" x 1"

+ Product Description Upgrade your HVAC system with our 4" Round Air Vent Supply Grille

16" x 3" Aluminum Spiral Duct Air Vent Grille Cover - Fully Adjustable Double Deflection HVAC Air Supply [Outer Dimensions: 18w X 5"h] 6in diameter + Product Details Size –16"w X 3"h Is The Size For The Duct Opening Measurement Only, Actual Front End Outer Dimensions Are 18" Width X 5" Height SEE IN DESCRIPTION HOW TO MEASURE A GRILLE Installs Directly On Round & Oval Spiral Duct No Frames, Box or Other Attachments Needed Commercial Grade Aluminum Will Never Rust Designed for Warehouses, Factories, Workshops, Gymnasiums & Restaurants Easy Unrestricted Air Flow For Your HVAC System 180 Degrees Double Direction Adjustable