Showerhead with external thread G1/2"

Have the problem with a broken showerhead in a hotel so i was searching for a thing that I can print. But most of them have an internal thread. And I need it with an external one.
So I designed one, inspiered by one that I found here, that works for me.
I'm sure that it could be optimized, but it works.
If you have suggestions, feel free...