Fastest charging USB

[Man In Black 805]

I was wondering what the fastest charging USB available is? The highest amp rate I can find is 2.1, is this the limit or is there anything faster? Would it be recommended to charge any faster?

 

[Darnell0216]

Anything beyond that will be wasted as the device's max input is ~1.9A (screen off) and 1.2A (screen on) set by the internal software.