This is the mark III version of my xo modeling board. The first try was ugly and the second used bread boards. It keeps getting larger. The bread boards fell apart and destroyed the components. This one seems to work well without hurting the components. I put the inductors outside the springs and the caps inside the springs. I run the wires from the board to the drivers so you can sit at the PC and make xo changes without running back and forth. The L-pad is free so I can connect it to level the tweeter and then disconnect it and check the values.