Dual output ports provide an option to power 2 devices at the same time. The right port (5V, 2.1A) can power/charge a Case Relay, TetherBoost, an iPad, or a tablet and the left port (5V, 1A) can be used for other portable devices including CamRanger, iPhones, iPods, Android Devices, PSP, SmartPhones, and many other USB devices. The Rock Solid External Battery Pack will provide up to 50 hours of power to an iPhone 6 and 20 hours to an iPad Air 2.
The power bank contains a rechargeable lithium-polymer battery, and an internal microchip controlling the voltage according to the device needing to be charged. So no matter which port you select it will never damage the device. When the power bank becomes depleted, recharge it the same way you charge any phone or tablet. Its small size and high-power capacity makes this device ideal for supporting your equipment on long photo or video shoots and during extensive travel.