A Zanker Flow Conditioner Plate for use in airflow straightening applications, such as small wind tunnels or special air handling testing. This is built to ASME MFC-3M-2004 standards. Just input the desired plate diameter into the second line of code and the appropriate model will be exported. If you would rather not mess with code then follow the following link to Thingiverse, select customizer and input your desired diameter there..

https://www.thingiverse.com/thing:3202602