12" 1/4" plate
The hole was not precise, but it worked, it did not look like it was drilled with a drill bit. This was not a problem, just an observation. The thickness was accurate. Edges were not sharp and must have been deburred (a good thing). The plate was placed on a bolt and spring hanger purchased at the same time. Once hung, it leaned a little forward and exposed a bit of the top of the hanger. A hole placement a little more towards the center would give more coverage of the hanger behind the plate. But that might also cause problems for the hook hanger if you decide to hang them with that hanger type, I am not sure. Overall it was a good value for the money and I would purchase it again.