Plug display cases question

[Slipknot]

I have questions about plug display cases if any of you can help me.

Assuming the cases are to be used to either put on a wall or carried to another location and put on a table or something, what holds the plugs in place? or are they just loosely placed in there and no way to mount to a wall vertically?

maybe some kind of nails into the back?

what is best for the backs? felt or foam?

I think having the lid on a hinge is wise and maybe also have some kind of hardware that can prop the lip open as well. Do they usually have real glass I assume, not plexiglas?

thanks for any hints or additional tips