We use '그거' for the already mentioned object regardless of distance.
If there is something near me and far from the person I'm asking and I would ask : "이거 뭐예요?" should she/he say: "그거 ABC"
If there is something far from me and near from the person I'm asking and I would ask : "저거 뭐예요?" should she/he say: "그거 ABC"