Not sure what to call this - just a question?

So this may be a question specific to just this hospital but I figured I would ask. I am still in my pre-reqs so I don't know much about nursing jobs but I like to take a look from time to time to see what is open. Some of the positions are listed as Yada Yada 3EP or 8EP or 11EP, etc. What does that mean?

Thanks in advance!