The file 'Gnat Funnel! 3D Printer Model' is (stl) file type, size is 13.8KB.
So maybe not for gnats, but this is a 3d printed approach attempt to trap those pesky fruit flies that comes with your bushels of supermarket bananas.
My wife had been using the rolled up paper funnel+ball pickling jar technique for a couple years with success. Google for details what to use, but we've been filling bottom 1 to 2" of the jar with a water, vinegar, and dish soap solution.
Disclaimer: I've not yet put the 3d version into the field, so don't know if it'll work compared to the paper method.
Enjoy!
gnat_funnel.stl | 73.2KB |