The AGUILAR GRAPE PHASER FACER for the base is designed to provide a faithful analog phase shift with two simple no-layouts.The Rate knob controls the speed of modulation, and the COLOR knob feeds a portion of the signal into the phase shift circuit, creating funky bass.[Specs] Input terminal: 1/4" standard jack x 1; Output terminal: 1/4" standard jack x 1 control: RATE, COLOR knob, ENGAGE switch power supply: 9V