DuraView’s attention grabbing colorful border protects US Letter and A4 sized paper inserts on 3 sides for easy exchange flexibility. Choose to keep the long side or short side of the DuraView open for horizontal or vertical installation orientation. You may also choose to have a 4 sided frame as well. Using DuraView to make your own custom signage is as easy as PEEL ~ STICK ~ PRINT ~ INSERT ~ DONE! Window Size is always 8.5x11