The ZVex Vexter Sonar guitar effects pedal is a tremolo pedal unlike any other. Unlike most tremolos, it can cut down your high gain signal to silence. It can also sound gorgeously transparent. It does other fun stuff like increase or decrease tempo, duty cycle (amount of time the tremolo is on in a given cycle), or both simultaneously on the fly. It also has tap tempo and a slew of advanced features (Attack, Release and Depth controls). Lastly, and perhaps most importantly, it has a famed ZVEX "Machine" circuit built right into the box.Plug your guitar into the input jack and your amp into the output jack (or you might mix it with other pedals). It can be anywhere in the chain, but if you are using it in "Machine" mode you might want to put it before other dirt boxes to hear it cut through those effects. The Sonar draws about 10mA and can be powered with a 9V battery or any standard filtered/regulated musical 9VDC power supply with a negative-tip barrel connector.