Wrought iron fixture from 18th century on outside exterior of buillding in Greenwich Village.
The bottom part of the wrought iron fixture is a heavy duty, swiveling wall bracket, used to support many things, such as signs. In this case, the bracket was ended with a small hook.
The upper part is a specialized attachment with the slightly larger upper hook braced by a riveted bar, doing the same work as the lower bracket. Note the riveted plates securing it to the lower bracket.
Sometimes, a block and tackle would be hung on the hook to allow a pulley and ropes to lift heavy objects, from the street to an upper window.