The D Addario Pedal Tuner Plus boasts the speed and accuracy of the original Pedal Tuner, plus two new features. First, it has a high-quality signal buffer, to maintain your sound across long cable runs and prevent signal loss through your effects chain. Second, it includes a programmable countdown timer to keep track of your set or session time. All of that combines to make a standout multipurpose pedalboard tool ” keeping you in tune and on time. Features: Onboard Signal Buffer 32-Bit Processor for Fast Response and Accurate Tuning Countdown Stage Timer Full-Color Vertical Display Power Requirements: 9V Battery or 9VDC (300mA) Power Supply