Screw one part into the ceiling and connect the other one to the object you want to hang.
Simply connect the two and rotate to lock them in place.

NOTE: The .stl files are only example files, which I used to mount my lights.

The mounting-overhang is made to slope outwards, to make it possible to print without support material.

Designed to be easily customizable using the OpenSCAD Customizer. Simply open the .scad file in OpenSCAD and select Window > Customizer from the top bar. Afterwards, you can configure the model in the panel. This allows you to change anything from screw hole diameter to overhang angle and baseplate size.