Mechanical Iris structure designed for 3d print. There are 5 leaves. When you rotate the "Drive Part"or the middle plate, the center hole can open or close gradually. The center hole is diameter 50mm, the outer size is diameter 110mm and thickness is 10.2mm. To assemble the parts togther,some M2 screws are needed. It is best to use resin material when 3d printing. And you may need to sand some parts due to the 3d printing quality. STL and STEP format files are included.