It's like other continuously-variable-pattern mics, I believe. I tried to find out the specifics by contacting them, but several weeks later they still haven't replied. Anyway, the other mics like this simply have a rotary pot that starts at "Omni" at one extreme, and as you rotate the control, ends up on "Figure *" at the other end. In between are various "shades" of Cardioid
(Wide, Hyper, etc.), I want to say that the control is varying the bias between the dual capsules to determine the directionality.

Hi Moon, sounds right to me, thanks for explaining that so well. I contacted Dusty (from Mojave) yesterday so maybe he will chime in here and tell us more on it.

Yeah, it looks like a really nice arrangement, definitely worth the upgrade from the 200.

All of my tube mics have this on the power supply. And technically I think its as Moon said.