This power bank won't let you down. Conventional power banks for recharging smartphones and tablets are often empty just when you need them. The Voltcraft SL-160 power bank has built-in solar cells that prevent self-discharge, as long as the power bank is stored in a suitable location, such as on a windowsill. In sunlight, the power bank recharges itself. Free and completely independent. Charging is faster via the integrated USB port. When the power bank is charging, a built-in LED lights up green. Once the power bank is fully charged, the LED turns blue. The power bank also features a flashlight and SOS function, ensuring you have light in the dark at all times and can attract attention in emergencies with sufficient bright light. Four integrated LEDs indicate the current charge status of the power bank.