It is not a physical product, what you get are digital STEP and DXF format files. You can manufacture parts and assemble the mechanism yourself.This sliding iris diaphragm is similar to a shutter mechanism. The shape is similar to Chinese ancient copper coins-a square hole inside a circle. When you move the Driving Button,the four blades in the center square hole open or close gradually. Most parts can be fabricated on a laser cutter.You need to prepare some metal parts,such as bolt, nut, pins,refer to the BOM in the package. The square hole is 80x80 mm, the outer diameter is 270 mm, and the mechanism's thickness is 12 mm. Part's thickness is 3 mm. IgnoreSTL,OBJ and FBX format files,they are just used to meet cgtrader's requirement. Ignore STL, OBJ and FBX format files, they are only used to meet cgtrader's requirement.Free 3DPDF file are downloadable: twothreed.comThis tutorial shows you how to assemble parts together. https://www.tanerxun.com/assemble-square-hole-type-sliding-iris-diaphragm/.html