The black Metal 4400 Rechargeable Battery Pack from Brunton is a compact, 4400mAh rechargeable power station. It features dual USB 2.0 and Micro USB output ports to connect most small electronic devices using their USB charging cables. With an output of either 1 or 2.1 amps, this power station is ideal for charging tablets, smart phones, MP3 players, cameras, or other small electronic devices. The permanent internal battery is charged using an integrated USB cable that can be connected to any USB port, a USB/AC plug or Brunton's Solaris 4 USB solar charger. The compact and lightweight Pocket Reactor is only 2.1 inches long and weighs 5.3 ounces. There is a power button and LEDs show if it is activated, charging, and the available power.