It's a great way to mangle CVs...as you'll see, the acronym means Shifting Inverted Signal Mixer. It's just as crazy as the sound of that implies. I'd have to say that as far as CV mixing/modifying devices go, this might be the do-it-all in 12 hp device. Even more twisted is that it can also do offsets and it can be used for audio in some strange ways. Lots of custom configuration jumpers, too.