These bottle to bird feeder adapters have been around forever - and this is a different design of one. This design minimizes plastic use, and gives other ways to suspend the feeder. Recommend thick string if using ring hooks to ensure bird does not get caught.
PETG is recommended.
The author remixed this model.
After uploading, realized someone else had a very similar design! Differences is that the dispensing pan is larger in the model by Renato. I have also added hooks along the ring.