Designed this as a prototype ring box for my son's wedding. The actual box will be made from oak. The right and left containers pivot on a 1/4" dowel which is the only way the base and the lid are connected.

I added a cavity in the bottom of each side and the base where I inserted a .31 x .11 magnet. The magnet acts as a "lock" and doesn't allow the sides to open without specific intent.

I also included an STL file without the letters if someone wants to import it in and add their own. The rough overall size is about 6" x 5.5" x 2".