The other port provides a 5V 2.1A USB slot that has smart charge capabilities, the smart port intelligently detects what your device.
One of the ports uses latest Qualcomm quick charge 3.0 chipset. This technology allows the device being charged to determine the power level it requires at any given point; this means the device is working with the most efficient and optimal power transfer rate. Charge your device up to almost 4X the speed of standard charging; up to 80% in 35 minutes!
The Sumvision 2 port wall charger is backwards compatible with Quick charge 2.0 giving you the option to charge devices that use previous versions of Quick charge.