Print in TPU. The iris was purchased from Cold Harbour Supply and has a outer diameter of 45mm. You can use the cap without the lens protector but it will overhang a little bit.
There is two versions of the model. There is a solid cap and a version with a hole in the center. The model with the hole will print solid (as seen in the photo) but provides a center marker for you to drill a custom sized hole.
The author marked this model as their own original creation.