The ArtBOKZ is as strong as a wood crate but comes flat to reduce freight cost. The size listed is the closest size to your portrait, painting, display, or framed art size. The thickness of your item can be as great as 3" down to 1/2". If you need a custom size, just call us and we will make it for you! Each ArtBOKZ comes with Foam Corners and Is ready for shipping! Watch the video at https://www.youtube.com/watch?v=vuWzDPZ5PtE&t=17s .