10" X 10" Sound Rated Steel Access Panel Felt Covered Door For Concealed Wall / Ceiling Flush Application With Slotted Lock - [Outer Dimensions: 11" Width X 11" Height] 8in diameter 75"H – fits a 30"

75"H – fits a 30" X 6" duct opening

Actual Filter Size – 31 3/4"w x 27 3/4" x 1"

+ Product Details Size – 24"w X 30"h is the size for the duct opening measurement only

Think of the diameter as a straight line from one end to the other

10" X 10" Sound Rated Steel Access Panel Felt Covered Door For Concealed Wall / Ceiling Flush Application With Slotted Lock - [Outer Dimensions: 11" Width X 11" Height] 8in diameter 75"H – fits a 30"+ Product Details Size 10" X 10" is the size for the drywall opening measurement only, actual front end outer dimensions are 11" Width X 11" Height High Quality High grade steel construction. Design 1mm galvanized steel material with sleek, shiny, durable white powder coat finish for an attractive look & high durability corrosion protection 15mm medium density fibreboard with felt cover and rubber sealing between the door and frame for tight security.