It is a spreadsheet that lists 300 or more draft eligible players and their avg rankings from a variety of web based player rankings.
It has a full draft list (teams and where and when they pick)
A sheet with team stats from last year. (such as offensive and defensive rankings)
It will have a sheet with combine results.
You can quickly and easily create mock drafts by putting a number next to the a college players name, this will populate the mock draft forum.
Essentially it is a way to make league mock drafts and also team mocks as well. (For example with the Jets you can filter it so that only jets draft picks are visible and then you can have a better idea of what players might be available for them at each selection.)