2A Input & 2.4A Output: 2A input can save half of the time to fully charge the 6700mAh portable charger ( please use a 2A or higher output charger); 2.4A output makes it charge other devices 2X faster than other chargers. The maximum input and output for the fastest and strongest charging experience. Exclusive iSmart Technology: Charge faster and smarter than others, automatically detects and delivers the optimal charging current for any connected device- ensuring the fastest and most efficient charge. Compact body, amazing capacity: Fitting in the palm of your hand, the 6700mAh upgraded capacity can charge iPhone 6, iPhone 6s for 2.5 times, and more than one charge for large phones like 6 Plus, Note 4, etc Unique Design: Made with an ergonomic design that is carefully matched with a gorgeous metal shell that will transform you into a style icon, while 4 status LEDs keep you informed of remaining capacity. Safety Protection: Ultra reliable A+ Lithium-Ion battery with over 500 battery charge cycles; short-circuit and over-current protection. This battery pack will automatic shutdown if a short circuit or overload output occurred while unit is charging.