It is a system that helps to keep the soil moist wherever it is needed in a flower bed, garden or flower pot. Tested with a 1.5-liter bottle of mineral water, it lasts up to 4 days, but all standard bottles are suitable, I recommend lubricating all threads with solid grease or petroleum jelly for water tightness, I used the settings 

0.4 nozzle
4 walls 
8 top and bottom layers
15% infill
or more

if necessary, a space left in the middle for cotton to be used as a filter
I created this one because I couldn't find a durable design, and this one is made strong and simple, no support is needed when printing

The printing orientation is shown in the photo

Update 05/31/2024 If the screw turns after tightening, simply increase the screw scale in slicer to 1% or 2% or even more, but in order for the threads to coincide, only the X and Y axes should be increased this will increase the size of the screw and allow you to tighten it

06/11/2024 don't forget to make holes in the bottom of the bottle, cut off the bottom completely "it will be easier to add water"

06/13/2024
there are three options, each for a bottle of a certain size, for soft ground choose the larger size
shorter - 0.5l
standard - 1l / 1.5l
longer - 2l

06/19/2024

I am adding additional screws, one printable is horizontal to the other, you need to screw M3 x 15mm screw, in any case, both are stronger