These simple discs keep insects from hacking my airRohr.  ☺

https://luftdaten.info/

You want to print two of them. They should be a tight fit and hold without glue. If they don't quite fit your contraption, you can scale the STL in your slicer or edit the included OpenSCAD file.

I had to cut two ribs on one side for the power cable and the air hose.