This is just a simple peg hook for a ½" French cleat system. Simple but useful. I printed with a 0.8mm nozzle in PLA with supports. Easily holds a hammer or 4' level. etc. I haven't pushed them to their limits yet. I suggest printing on its side so that layer lines don't face any large shear stresses. As pointed out by V8rick you need to add supports under the hook part.
The author marked this model as their own original creation.