Steel conduit

[Buzz-light-bulb]

my thought exacty nicke--a lug- at least the clamp.s on steel conduit
take note poster

I'm fully aware about the lug

 

[Lucien Nunes]

Looks like 1" lug grip conduit to me, held to the wall with crampets. Can't see if the tee is an inspection type - it seems to have the outline of a cover. The stub above the tee seems to have a rubber female bush where cables used to exit.