I've got two Mesa/Boogie MIDI Matrices I've decided to let go. These are extremely rare; Boogie made less than a pallet of them in the 80s. They are a two rack space midi controlled switching system. I have two versions; both have 6 FX loops, 10 function switches (for controlling gear), full midi control, & loop level control. The one of top has two A/B sections, and loop output level control. The bottom one is slightly deeper, and has 4 additional parallel loops. These are great for people with lots of effects, or guys who are running more than one preamp/amp at once. I was able to run 10 pedals and my amp in one rack, and switch everything with one click. Sound confusing? Trust me, these are the easiest switching systems in the world to use. Email me with questions. $300 each, or $500 for both.