This Cool CST1 Smart Touch Tuner is ingenious. With a foolproof touch screen and USB charging capability, there's no need to worry about batteries, just plug this right into your computer and after one full charge you've got about 600 tuning sessions (about 20 hours total). Its slightly larger screen makes it easy to see when tuning, and ridiculously simple to use. You've got A4 calibration, Chromatic, Bass, Guitar, and Ukelele modes, too. This Cool CST1 Smart Touch Tuner includes one USB charging cable.