Zoom gear that fits over a Panasonic 12-60mm lens for use in a Nauticam underwater housing. Fit can be a bit tight. Need to install from the rear of the lens before putting lens on camera.
This work is based on this one: https://www.thingiverse.com/thing:2500699
And finally I redid it from scratch, thanks to freecad and InvoluteGear i just discover !