This Outdoor Recreational / Emergency Preparedness 6 function powerhouse not only has a 3.7V 4000mAh battery, It charges itself with a .55W / 5V solar panel.  Included is a USB cable that allows one to charge the powerful battery from your computer or home outlet, or in reverse you can charge your portable devices like your smart phone, tablet, or camera! This incredible little lightweight unit also doubles as a 6 function light with emergency strobe to notify your rescuers!