Tune your guitar anywhere, electricity-free with the Tascam Solar Guitar Tuner. This guitar tuner has an internal battery, powered by a solar panel. It can run on continuous battery operation for six hours and also be charged by USB in case you rock and roll all night and party every day. The tuner has four modes: needle, strobe, fine, and meter. It has 12 tone equal temperament and detection accuracy within 1 cent (A = 440 Hz). I don’t know what all that means either, but I do know that it’s pocket sized and has a standard mono jack and a built-in microphone to pick up the sounds. Rock on.