Sun-Plugged bags are mobile renewable energy power stations designed to charge virtually all hand-held electronics. Embedded in all of Sun-Plugged's bags are tough, lightweight, waterproof solar panels. This three compartment backpack features a waterproof, scratch resistant, high efficiency monocrystalline solar panel. Our Max Solar Backpack produces 4.5 watts of power, so 1 hour in direct sun will power over 3 hours of iPod playtime or 1.5 hours of cell phone talk time. The Max Solar Backpack charges virtually all handheld electronic devices! All Sun-Plugged bags come with a custom battery pack with an embedded solar panel that stores any surplus power generated, so it is available when you need it - not just when the sun is up. The battery even charges itself in the sun!