I have no idea- Charlie has had that page up for years with nothing further. I suspect it's pretty much a point device- just effective near the target.
I can grasp the theory easily- in practice? How powerful a magnetic field can be generated, and how fast can you collapse it? That's what generates the pulse.
The device is charged by discharging a capacitor bank into it, and since it gets destroyed, it could be right to the point of failure. The implosion charge would crush it in milliseconds.
Like a flash-bang only for electronics?