Changed the model a bit, added a connection to 50mm fan and blocked the contained bottom from airflow. Acts as a container for active carbon for me. Many other uses can be applied. 

In the picture I have a adapter to fit 60mm fan on it, figured out that I did not have 50mm fan afterall :D

The holes for screws or bolts accidentally came out too wide 8mm, the measure was radius, not diameter :D

For the use: when filling the container with activated carbon, remember to shake the stuff tight to make sure the air flow through the carbon and not the caps between the pellets.

Printed in PLA, use some extra perimeters or print it solid.