20" X 20" Aluminum Access Panel Gypsum Board/Sheet Rock Door For Wall / Ceiling Application (PUSH-LOCK DOOR) With Frame - [Outer Dimensions: 21" Width X 21" Height] w36h36 SEE BELOW IN DESCRIPTION HOW

SEE BELOW IN DESCRIPTION HOW TO MEASURE A FLOOR REGISTER

For HVAC a 1/2" fitting

+ Product Details Size - 4"w X 26"h is the size for the duct opening measurement only

the actual front end outer dimensions are 10" in diameter

+ Product Details Size - 32"w X 14"h X 2"d (for duct opening measurement only)

20" X 20" Aluminum Access Panel Gypsum Board/Sheet Rock Door For Wall / Ceiling Application (PUSH-LOCK DOOR) With Frame - [Outer Dimensions: 21" Width X 21" Height] w36h36 SEE BELOW IN DESCRIPTION HOW+ Product Details Size 20" X 20" is the size for the drywall opening measurement only, actual front end outer dimensions are 21" width X 21" height High Quality Strong and sturdy aluminum built to last and never rusts. Made with gypsum sheetrock for a seamless finish Design Aluminum frame material with sleek, shiny, durable white powder coat finish for an attractive look & moisture resistant to prevent mold & mildew buildup in indoor or outdoor