An effect similar to a tremolo, but what makes the Bubble Machine different is an option that allows to select patterns that will change over time. A pulsing LED shows you the pattern before the effect is engaged. This makes it easier to set it to the tempo of your music. It also has an expression pedal connection, allowing you to control the speed with most any passive volume pedal that has an resistance between 100K and 250K ohms.
The Bubble Machine is a true bypass all analog device that uses top quality components throughout.