It is a double sliding door mechanism, similar to a mechanical iris or shutter mechanism.Most parts can be laser cut or 3d printed.STL-they are for 3d printing;DXF-they are for laser cutting;OBJ,FBX-you can delete these files, I upload these format files only to meet the platform's requirement.More: https://www.tanerxun.com/mechanical-iris-shutter-mechanism/.html