Does the iPhone 5s take 5V,1A or 5V,2.1A charges?

Hi. It is advised you use the Official Apple Adapter for iPhone 5S, as other chargers might have some issues (especially regarding electrical security) : http://store.apple.com/us/product/MD810LL/A/apple-5w-usb-power-adapter?fnode=9c0 6d597f6022c074cff20782f7c98deef4b5480371…

It ships with the 1 amp charger but will also accept the higher capacity, 2.1 amp charger.