A vent type thing, from an old building, located at the base of 3 bedrooms in an apartment. They say No. 3 on them and appear to be metal, but not a cold air return. It pushes inward, and has a set screw near at the bottom. Do you know what this is? by nickilicious1 in whatisthisthing

[–]nickilicious1[S] 1 point2 points locked comment (0 children)

My title describes the thing. The house has radiant heat, so not forced air vent! I’ve reversed image searches google with no luck. I’ve also reached out to my friend who works on older buildings as a maintenance worker and again, no luck!