If you really want to understand Fortress, these 2 DVDs (incl. Paperback with notes and tablature) are indispensable! The sophisticated production equipment is shown, above all, of course, the hours of private lessons by the two priceless. Patiently and up to three camera angles all song sections are alternately presented by the two to the smallest detail. The guitars are tuned down, but not always the same for both. Both the interaction, as well as in the individual parts, are the differences between the two obviously .Even the sound difference between the two PRS and the half-stack of the two (Tremonti: Mesa Boogie Rectifier, Kennedy: Diezel Herbert) is audible. But precisely because the two complement each other so well. Although I am a guitarist, but I learned a lot at the first view u. Listen. Highly Recommended!