16" x 3" Aluminum Spiral Duct Air Vent Grille Cover - Fully Adjustable Double Deflection HVAC Air Supply [Outer Dimensions: 18w X 5"h] Black } /* MORE SPACE BETWEEN

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+ Product Details Size – 24" x 24" with 10" collar T-Bar drop ceiling perforated return grill - metal back casing

4" X 12" Is The Size For The Duct Opening (floor/vent hole) Measurement Only

Actual Filter Size – 7 3/4"w x 15 3/4" x 1"

16" x 3" Aluminum Spiral Duct Air Vent Grille Cover - Fully Adjustable Double Deflection HVAC Air Supply [Outer Dimensions: 18w X 5"h] Black } /* MORE SPACE BETWEEN16"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