The Xtar Over 4 Slim is a rapid charging device that can safely charge x2 18650 batteries from empty in 30 minutes.
The Over 4 slim has a multitude of options whether it be 4.1amp charging, 2amp or 1amp charging you can choose what rate to charge at across x2 different ports.
In addition to the 2 main battery ports on the side of the device are x2 USB charging ports which both output at 2.4amp.
As you can see the Over 4 Slim is giving you access to not only fast charging of cells but of mainstream USB devices as well such as mobiles, tablets etc.
The Beautiful LCD screen will show you all the information that you expect when charging your cells.
The powerful chip in the devices will automatically charge your device at the correct rate based on internal measured resistance.
Do not worry about safety, the Xtar Over 4 Slim has built in temperature monitors that constantly oversee the charging cycles work to insure safe, powerful charging.