It's a famous buffer. They say the original one is far overpriced. You love it or you hate it.
Think about an entity that is half men and half horse and you understand what we are talking of.
My take carries two more switches. One switch for choosing if you want a bypass or a unity gain buffer when you are in the bypass mode. The other one will set two different basic voicing. One voicing is like the original stompbox, the other one is much thicker and to me much better.