PVI Aluminum Doors are a perfect solution to letting a pet go in and out without constantly opening and closing a door. Prairie View Industries animal access doors are resistant to warping, rusting, or breaking. Doors fit tight & install easily with relatively no maintenance. Flange on side allows pet to easily use the door. Measure the hole/opening & the door size will need to be 1 in. larger on each side for a weatherproof fit. Inserts accommodate a maximum thickness of 6 in. & a minimum thickness of 3. 75 in. & are placed between wall studs to help prevent chewing.