The world's first solar-powered instrument tuner is the new TASCAM TC-1S. The TC-1S charges its battery from a bank of solar cells on the front panel, and a USB input is also available for quick-charging when you're completely in the dark. It's wrapped in a shock-proof silicon cover, available in six colors, and a strap and clip keep it charging all day long on your gig bag. At a price under $40, every planet-conscious musician is going to need a TC-1S.