When you've got to have the classic tremolo made famous by vintage '50s amps, get the Behringer Ultra Tremolo UT300. The classic surf music of the '50s and '60s might not have even happened if tremolo hadn't come along. Vintage amps produced this intriguing effect by pulsing the volume of the instrument signal at a user-adjustable rate. The UT300 pays homage to this legendary sound, bringing it up to date for modern surf freaks. With its dedicated Rate, Wave and Depth dials, you can shape a pulsating tremolo that nails every sound from rowdy rockabilly and surging surf, to modern space rock. A red LED tells you when the effect is activated, and you can power this groovy stomp box with either a Behringer PSU-SB DC power supply (not included) or a 9 V battery. A top quality on/off switch maintains excellent signal integrity in bypass mode.