A mixer with three channels of either attenuators and/or attenuverters (each channel is switchable).  There is a jumper on the back to normal a 10V signal into the first channel so you can add some harmonics through clipping one side of the wave.  It also has pin header IN and OUT so it can be chained with multiple units and work directly with our mixer lineup.  This is an easy way to add some simple mono channels with no sends.