Tube for attaching to a swimming pool skimmer plate.
PETG - I was able to remove bridge supports from the inside by pliers without bigger problems, however some smaller parts of the support basement will probably remain there (PETG sticks too much). Shouldn't have any negative impact regarding to the functionality.
When printed in PETG, it will probably need some slight grinding/smoothing using a sandpaper or a file in order to get completely rid of the bridge supports on the outside of the lowest diameter tube where the smoothness matter.
Better to use 0.2mm layer height probably for PETG. 0.1mm is too smooth for PETG I think.
The author hasn't provided the model origin yet.