All the guitar theory you will ever need in one page (front and back)! I even loaded it on my IPad so I have all my reference info in one convenient place.
This is a reference tool. Some basic knowledge of theory will assist you in understanding the information provided. But even if you don't have an understanding of basic theory, this will guide to know precisely what is important for the learning guitarist to know.
I use this tool all the time in my personal practice to reference which chords belong to which keys, to look at chord formulas, intervals, scale patterns, and the fretboard.