Gardenhose / gardena to ¾ inch thread, commonly referred to as device adapter or Geräteadapter. Needs an O-Ring that can be found with my other models. Print in high quality for a good thread. The part where you screw this in needs a sealring. Happy watering :)

Disclaimer: I use the term Gardena as a reference term for the famous garden hose connecting system. I did not take any replicas from their designs or IPs specifically. I did my measurements and testfits on *any* system adapter I had laying around without the knowledge who made it.