Instapark Mercury 4S Ultra-slim Portable Solar USB Cell Phone Charger with Built-in 2,000 mAh Rechargeable Battery Pack for Apple iPhone (all generations) & other smart phones, Color Black 4 Watts high-efficiency mono-crystalline solar panel with foldable design offers excellent portability, ideal for emergency preparedness, backpacking, camping and other outdoor activities Built-in standard female USB port for directly plugging in iPhones, Android-based smart phones, Blackberry & other USB compatible mobile devices Charges built-in 2,000 mAh Rechargeable Battery Pack and external device at the same time Measures only 7  X 4  X 1  inches and weighs 7.6 Oz Weather-resistant design, backed by 1-year manufacturers warranty