Summary

a corner bracket to hang stuff from a 1/2" dowel

one end of the dowel I had was smaller than 1/2" so the hook end is smaller, scale up or make your own adaptation.

It is designed to have a spring in the hole at the top extend to the retaining ring on the dowel. You can drill holes to set the position which tensions the spring or use a zip tie to hold it in place.

The dowel is held in place using a 9d finish nail for a pin and same dropping one down the hole at the top for the spring. A safety pin was used to affix it to the dowel collar/retainer.