This very small shelf bracket is cast iron and old. I envision a narrow plate shelf atop this bracket.
The bracket measures 2 1/2 inches one way and 3 inches the other way. It is only 5/16 inch wide. There is a hole at each end in order to screw the bracket to the wall and shelf.
Here at the Old Hardware Store, we haven’t ever seen anything quite this delicate, old, and sturdy.
Screws are not provided with this one.