It is a special box or a functional unit. When you drive the handle(or the bolt), the blades open or close gradually. It is not lightproof,and it is not a gear reduccer . It is bevel gear type. When you 3d print the parts, you need to take care of the parts' quality. And due to the part's quality, there may be some hand work. Resin material is the preferred material. FDM technology should not be good enough now,so if you use ABS/PLA material, usually you need to make some change on the model or do some handjob after printing.You can get the newest discount code from sidebar here: https://www.tanerxun.com/blog
You can design the bottom box by yourself and then assemble it other parts by bolts.It can be considered a gift box design plan.To assemble the box, you need to prepare some metal parts: M3X12 screw, M3 nut, M3X10 screw, M3x16 screw.STEP files are included. You can ignore the fbx,stl and obj files, they are just for cgtrader's requirement.