Passepartout, Photo Frame or Shadow Box. Glue-less, hollow, double-walled tray.Can also be used as box insert.
Create a photo frame for your photo‘s with a posh, wide frame.
Enter the dimension of the “inner space“ (the size of the picture or object to display), together with how thick and wide you‘d like the border of the frame to be. The final model will be larger, because of the width of border of the frame. The model can be constructed without using glue, although a bit of glue won‘t hurt.
When used as an insert, you might not need the inner part.
For assembly
instructions, have a look at the YouTube-movie