A screw on funnel to fit standard 2l soft drink bottles.
I designed it to refill a 3d-printed bird-feeder which uses 2l bottles to hold the seed.
remixed from:
https://www.printables.com/model/1200637-bird-feeder-reduction
which is part of the bird feeder I used:
https://www.printables.com/model/1148339-bird-feeder-bottle-wide-cap-48mm
It will probably have other uses - I use the 2l bottles a lot, for mixing fluids for my car, and things like citric acid rust remover.
probably best to print from ABS/PETG since (for me at least) it's likely to get battered around a lot.
It should print without supports
The author remixed this model.
re-used the threaded part