It is a simple mechanical iris structure or shutter mechanism-Hexagon cutout.It can be open and closed gradually.Most parts are designed for laser cutting or 3d printing. You need to buy some screws to assemble them together.STL and STEP format files are included in the attachment. After you get the files, ignore the obj and fbx format files, they are only used to meet the platform's requirement.More: https://www.tanerxun.com/mechanical-iris-shutter-mechanism/.html