The lil’ gadget is small enough to clip onto a belt-loop or guitar strap. The device has a microphone but also features a 1/4-inch input for bass, guitars and other electronic instruments, according to TASCAM, which makes the device.
The solar tuner can fully charge in light in about 25 minutes, and its battery lasts for up to seven years. So even if your traveling troubadour is actually a denizen of the dark, the tuner should last for a long time between charges.
If for some reason they need to tune their instrument for more than six hours straight in the dark, they can also charge the tuner up via a USB port. And it doesn’t cost an arm and leg—it’s under $40.