Boss RT-20 Rotary Sound Processor.
 
	
Authentic rotary speaker sounds via COSM technology
	
Slow/Fast transition time is adjustable from gradual to rapid change; optional Expression pedal can
	
Onboard Overdrive effects
	
Adjustable mix balance between Treble Rotor and Bass Rotor
	
4 types of sounds, from standard rotary speaker effects to rock-oriented tones, UNI-V, and more