As you know, drip irrigation is one of the most economical. This thing is a tap for drip-watering plants.
The water tap is designed to be connected to a 6-7 mm inner diameter with a silicone or rubber hose. The range of operation is approximately 1-100% of the opening. 0% of the opening can not be provided by such a design, however in my opinion the appearance is rather steep. However, 1-100% is quite a suitable range for drip irrigation.
After printing, it may be necessary to finalize the thread with a tap and die for easy movement. I also think that it is necessary to use the blowing of the parts during printing. (I printed without blowing, because I do not yet have a fan)