These hooks are designed to clamp on to 17mm vertically mounted plywood or similar (shown in pictures). While quite specific in their use, you are welcome to modify for your own needs, or use it as inspiration for your own project.
More details of this project on my blog https://edditiveblog.wordpress.com/2018/06/11/3d-printed-hooks/
No support required.
Postdoctoral Researcher and massive 3D printing geek! My name's James Novak and you can follow the stories and experiments behind my designs on my website http://www.edditive.com or track me down on Instagram or Twitter: @edditive