represent 1st round draft talent, 247Sports grades only the number of 1st round picks as 5*, but when you combine the other services for the composite, you can add a couple more, but for the last 10 or so years, this has been the working model for 5* grades for the most part.
When you take into consideration how few total college football players actually get drafted, hitting at 65%+ accuracy and draftability for a group that small is actually pretty impressive.