http://www.ckkelectronic.com/product/frogman/frogman.html The Frogman is an optical Tremolo with all the right features. The speed and range controls have a wide range giving you a large variety of tones. The volume knob helps compensate for any volume drop when the pedal is engaged and even gives you a boost if needed. The Frogman also sports a wave switch that allows you to go from subtle to throbby to choppy.