22" x 22" Plastic access door
The 22" size fit perfectly between ceiling studs. Plastic holding edges don't work perfectly, but I bought some plastic screen holders and put a few around the door side frame to hold it in. They rotate out of the way if I want to remove the door. Two doors had the plastic hinge break off one side, but since I added the plastic screen clips, not a problem. Took me about 45 minutes to cut hole in sheet rock and glue in door. Let it set for 24 hours while clamped with 12 clamps. Will install a few more if I need to fix water pipes in attic. Attic is only 2-3 feet high, these doors makes the repair job doable.