UPDATE 25/04/2024:

Added a second version with wide stream - useful for covering bigger area

This is yet another adapter cap that screws onto any regular PET bottle (that has PCO28 thread) so that it can be used as a watering spout - useful for gardening, for example. 

There are 4 versions. They differ by presence of a breathing channel (so that flow can only be controlled either by gravity or squeezing the bottle) and stream shape (narrow or wide).

The models are optimized for ease of printing and ease of use - there are no overhangs of more than 45 degrees (no supports required!) and the nut is decently sized. Infill is only required for the first 15 mm (for the nut section). Also, “Random” seam placement should be used for slicing so that a good seal is maintained when mounted on a bottle (to avoid seam acting as an air channel).

There are several stabilizing bridges that connect two pieces together - they should be broken after printing by twisting and pulling the two parts apart (or just use flush cutters if you have them)