Duatt is a dual-channel active/buffered attenuverter and summing mixer. Each channel has a knob, which can function as a unipolar attenuator or a bipolar attenuverter, depending on the setting of its corresponding two-position polarity switch. It’s a versatile and super handy utility module that will find its way into almost any patch you make! Each input is normalled to a built-in +5V DC voltage source. With nothing plugged into the jacks, each knob controls a voltage range of 0 to +5 V or -5 to +5 V depending on the position of the channel polarity switch. Channel A’s output is normalled into the output of channel B for mixing duties, and channel A has has a 2x voltage multiplier switch, allowing you to double the voltage sent into Channel A. This used module is in great condition and comes in the original box.