The Nitecore UMS4 is an intelligent USB four slot charger, with QC input available for speedy charging. The total maximum output is 4000mA or 3000mA when using a single slot. ... However, you are able to manually change the charging settings, such as the voltage (3.7V, 4.2V or 4.3V) and current (from 300mA - 3000mA).