Boss RT-20 Rotary Ensemble - UsedThe Boss RT 20 Rotary Ensemble encorporates the company's COSM modeling technology to emulate classic rotating speaker sounds heard on countless recordings. Part of the Boss Twin Pedal series, the left footswitch turns the RT 20 on and off, and the right footswitch toggles between slow and fast rotary speeds. The user can control the individual levels of dry and wet signals, and there is even onboard overdrive which stylistically varies depending on