I'm trying to mount a heavy ceiling fan but ran into a unique ceiling box I've never seen before. Two bolts come down from the metal horizontal piece and pass through the plastic box.
This was the first set of pictures before I realized the box wasn't mounted by anything:
Then I realized it came off so here's the next set of pics:
Is this safe to mount a heavy fan to? Should I get nylon locking nuts and just secure with those bolts?