The Ultimate Outdoor Gear Goods FOR Mountaineers: SOLAR RUCKSACK WITH A STRONG LED LIGHTS It will provide light for upwards of 6 hours The solar rucksack is the ultimate rucksack as it combines a high-performance solar charging devices with a USB strong light source. Dual Voltage output (4.3V&5.0V),suitable for charging almost all digital products, such as IPHONE and Blackberry even charging LED flashlight and headlamp. It also will provide light for upwards of 6 hours as long as you have the USB LED lights