This is a Japandi style soap dispenser specifically designed for the foaming soap dispenser heads with a 38/415 style thread. The diameter of the threaded part 40 mm. The original dispenser that came with the soap had a diameter of 39mm with 1.5mm deep threads. 

Important Note: Where you put the seem when printing matters quite a lot to keep the dispenser watertight. Check out my 3mf file to see the seem I painted.

Let me know if you need it for other style dispenser heads.

You have my permission to improve the model, share it, produce it, sell it. Just don't re-upload it without any changes (basically don't have malicious intent). I added the STEP and SolidWorks files so that you can edit easier. If you are using Onshape, you can copy and edit the entire project using the link below.

→ Model link on Onshape ←