These new USB batteries from JoyeTech have a built in USB mini port in the end. It functions as a USB passthrough and charges the battery from most any USB port. These 650 mah high capacity eGo USB batteries will last almost half of a day with normal use, and with a USB port or car cigarette lighter to USB adapter nearby you can charge them almost anytime and anywhere. Just plug in the included USB cable to your USB port or power source and after the red LED turns off, the battery is completely charged. The built in 5 click on/off protection makes them perfect for travel, or carrying without having to worry about them activating in your pocket, purse etc... To turn the battery on press the button 5 times rapidly. To turn the battery off press the button 5 times rapidly.