Ashlar pillar that delineated the Via Gabina and separated it from the area F complex. It's similar in nature to the other pillars along the road (5721, 5722, 5723, 5724, 5727, 5728, 5729). This pillar is close to the ramp leading into the complex, so it might have formed part of the entrance to it, along with 5724.
Tufo pillar W of 5724 along Via Gabina