http://www.roland.com/products/en/RT-20/
Today BOSS proudly announces the newest member of its Twin Pedal series — the RT-20 Rotary Sound Processor. Employing COSM®-modeling technology, the RT-20 authentically reproduces classic rotary-speaker sounds. It offers adjustable Rise Time, Horn and Bass speed, Overdrive, and more. And not just for classic twirl, the RT-20 can be used to create unique overdrive and pulsating effects as well. This pedal sounds amazing, and offers a stunning graphical view of the virtual rotors on its built-in display.