18" X 4" 2-Way Air Supply Grille – Steel HVAC Vent Cover with Damper, Wall/Ceiling Register, White 6" Round Duct Pipe + Product Details Size –

+ Product Details Size – 6" x 16" or 16" x 6" is the size for the duct opening measurement only

actual front end outer dimensions are approximately 16 5/8" width X 38 5/8" height

40" x 16" Aluminum Spiral Duct Air Vent Grille Cover - Fully Adjustable Double Deflection HVAC Air Supply

Secure Locking Mechanism – Features a permanently attached eight-tumbler lock with a supplied key for added security

actual front end outer dimensions are approximately 24 5/8" width X 31 5/8" height

18" X 4" 2-Way Air Supply Grille – Steel HVAC Vent Cover with Damper, Wall/Ceiling Register, White 6" Round Duct Pipe + Product Details Size –+ Product Details Outer dimensions: 19. 75"W x 5. 75"H fits a 18" X 4" duct opening Durable stamped steel construction ensures long lasting performance Designed for sidewall and ceiling installation with included screws Multi shutter damper with easy lever for precise airflow control Smooth powder coated white finish for a sleek look and scratch resistance + Product Description Maximize your homes airflow with this premium Air Supply Grille air supply