18" X 18" Plastic Access Panel Removeable/Reversable Door With Frame For Concealed Wall / Ceiling Application - [Outer Dimensions: 20" Width X 20" Height] fixed bar + Product Details Perfect Fit

+ Product Details Perfect Fit & Easy Sizing - Designed for a 26" x 20" OR 20" x 26" duct opening (measured at the opening)

actual front end outer dimensions are approximately 28 5/8" width X 18 5/8" height

actual front end outer dimensions are approximately 30 5/8" width X 38 5/8" height

actual front end outer dimensions are 29

Actual Filter Size – 35 3/4"w x 7 3/4" x 1"

18" X 18" Plastic Access Panel Removeable/Reversable Door With Frame For Concealed Wall / Ceiling Application - [Outer Dimensions: 20" Width X 20" Height] fixed bar + Product Details Perfect Fit+ Product Details 18"w X 18"h is the size for the drywall opening measurement only, actual front end outer dimensions are approximately 2" wider. Most common access door Plastic Frame Easy Installation Just apply caulking or glue to the back of the frame Put in frame and lock the door into place Includes slots for a screwdriver or other prying devices Hinges on the top and bottom The door can be easily removed with a slight squeeze Installation