XTAR SP1 charger is a single slot lithium-ion charger based off the popular SP2 model. This li-ion battery charger is portable and offers three charging current options (0.5A/1.0A/2.0A). Like all Xtar chargers, it comes with a built-in over load, short circuit, and over-heat protection system. This SP1 charger is great for the most common batteries 14500 and up to 18650. It can also work as a USB battery backup offering a low voltage output port where you can use your batteries to charge your other USB mobile devices such as your smart phone.