From MXR:

The MXR Uni-Vibe Chorus/Vibrato delivers classic textures and tones with a smaller footprint, a simple three-knob interface, and true bypass switching.

This pedal can be powered by a 9-volt battery, a Dunlop ECB003 9-volt adapter, or the DC Brick, Iso-Brick, and Mini Iso-Brick power supplies (not included).