Underwater Quadripod Project - Custom port for two balls

This is the main part of my project : build a quadripod for my Nauticam NA-GH3/NA-GH4 housing ...

You have to buy 4 balls (or print) such as this one: https://www.thingiverse.com/thing:2846038 and 4 screw and 4 nuts.

If you can read french here is a long article on my blog: http://e.garluche.fr/post/2018/04/17/Realisation-d-un-quadripode-pour-caisson-photo-sous-marin-