Special unit only. This is one of the earliest units of the Special, which began production after the highly regarded units up to number 250 were made. While the VIVACE tends to be difficult to handle due to its unique bulging bottom, the Special's bottom doesn't overreact, responding well to nuances in your playing and making it easy to control. It's a pedal with amazing three-dimensional sound. The image is that you can control the distortion of overtones with the nuances of your picking. The right knob adjusts overtones, and the Special's effect is more noticeable than the standard Vivace, so please try it. (There's a very useful point if you get the hang of it, and I'll give you a lecture if you don't understand.) Will be shipped within the scheduled period.