Threaded Container bottom to bottom connector
thingiverse
I accidently printed to bottom parts and got that idea. Its not perfect yet.
Download Model from thingiverse
With this file you will be able to print Threaded Container bottom to bottom connector with your 3D printer. Click on the button and save the file on your computer to work, edit or customize your design. You can also find more 3D designs for printers on Threaded Container bottom to bottom connector.