This was made as test print for other project: 

https://cults3d.com/en/3d-model/home/alien-wall-mounted-hanger

Printed with PLA

Quality 0.2mm (I printed with 0.16mm)

No supports

Infill 10% (as minimum)

Assembly:

Print 5pcs of pins and glue them in one of the sides.

After that glue both sides together.

Note: 

Before applying any glue please preassemble and check if everything fits tight. 

Feel free to change wall thickness and infill density.

Usage:

For hanging stuff, I mean it is up to you.

Installation:

Wall hanger I installed wide end down with 2pcs countersink woodscrews 4x20 (mm) or it depends on what surface you want to install it.
After all is finished simply align hanger back slot with wall mount and pull it down and it should sit in its place. 

Please leave like or make 👍