Catalinbread Formula No. 5 50s Tweed Overdrive Guitar Pedal The Formula No. 5 delivers vintage Tweed amp tone The tone circuit functions as either a bright cap or as a treble rolloff depending on where the gain is set Functions as a great foundation for fuzzes and boost pedals Can be powered with a standard 9V battery, or a regulated center-negative 9V - 18V DC power supply