This looks like an outlet with only one receptacle, but why?
It's mounted about 7' up, in a basement-level room in a school building. It is stamped 15A/125V, but I've never seen something like this before.
My question is, is it indeed a standard (US) 120vac outlet, can I plug regular things into it, and why does it look so strange/why does it only have one receptacle? Also, what's that little hooky thing for at the top?