12" X 12" Aluminum Insulated Fire Resistant Access Panel Door For Wall / Ceiling Application (Lock and Key) With Frame - [Outer Dimensions: 13" Width X 13" Height] Grilles + Product Details Size –

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

40"w X 16"h Is The Size For The Duct Opening Measurement Only

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

+ Product Details Perfect Fit & Easy Sizing - Designed for a 12" x 36" or 36" x 12" duct opening (measured at the opening)

+ Product Details 6"w X 9"h is the size for the drywall opening measurement only

12" X 12" Aluminum Insulated Fire Resistant Access Panel Door For Wall / Ceiling Application (Lock and Key) With Frame - [Outer Dimensions: 13" Width X 13" Height] Grilles + Product Details Size –+ Product Details Size 12" X 12" is the size for the drywall opening measurement only, actual front end outer dimensions are 13" width X 13" height High Quality Strong and sturdy aluminum built to last. Design Aluminum material & color to give your space an attractive look & provide high durability corrosion protection no rust. Built in tumbler lock and key is provided Easy Access Provides easy access for HVAC, plumbing, electrical, crawlspace etc.