Used once, or twice years ago, It`s wired for 2 x 9v batteries hence I didn`t use it much, but I tried a couple 9v batteries new ones in it, the back 3 screws 1 missing, it acts like a more of booster sound with not to much power flange, I always was going to parallel the batteries and put a 9v Radio Shack jack on it by drilling a small hole then solider a plug to plug into to my 9v board and try again with the pedal, but did not, So yes you have to buy 9v 2 batteries to make it do what I described as is as described best I can