The Harmonic Bridge:    The Harmonic Bridge is a patented invention of Bob's that straps to the guitar neck at a harmonic point, usually at the 12th fret.  It looks a bit like a capo, but instead of pressing the strings down, it just barely touches them to produce a harmonic tone when the open strings are played.    The really cool thing about the Harmonic Bridge is that it doesn't prevent you from playing normally.  When you press the strings down with your left hand, the strings break contact and play normally again.  It's only the open strings that get the harmonic effect.    The Harmonic Bridge can be adjusted to apply the effect only to selected strings, allowing all kinds of note combinations and progressions that would normally be impossible to play.  Phoenix Song is loaded with examples.  Bob uses the Harmonic Bridge on nearly every tune.    Unfortunately, Harmonic Bridges are not yet available for sale.  Currently, they can only be made by hand, and would be fairly expensive to produce. Bob is looking into mass-production options, but no decision has been made on how to manufacture them, or what the retail price would be.    Stay tuned.