Updated, since I missed including one inner part (splicer) - Jan 11, 2024.

A simple camera mount used to monitor my printers using a now older Yi Dome Camera (2018 Model) on a 11/16" (17.3mm) white painted shelf.  I designed it hollow to allow a hidden USB mini cable to be feed through to the camera.

The insert should be the only part that will need supports.  Printing the rest should work without supports, if you print the body as modelled and the head upside down.

On my shelf it fits with friction only and doesn't require a fastener.