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