The Rechargeable Eclipse Headstock Tuner holds up to 24 hours of tuning time per charge. With the included USB cable, players can simply plug into any USB port to charge up. This new Eclipse Tuner still has multi-swivel action, an extra bright LCD display, and auto power-off, but now, players will never have to change the battery again. With this new rechargeability feature, on top of the full color vertical display and easy to use clip-on functionality, Eclipse provides excellent value to any player. D’Addario electronic tuners are designed by musicians for musicians featuring intuitive features, easy to read displays, and exceptional tuning accuracy.