It's a very high quality charger that can charge up to 2 batteries at a time, at 500-1000mA charging rates.
It tells you the charge levels via LCD screen. It's compatible with most 3.7V Lithium Ion or Li-Mn batteries such as 10440, 14500, 14650, 18500, 17670, 18650, 18700, 26500, 26650 etc.
*Note that this charger should NOT be used with the IJOY 20700 or 21700. It is not long enough for that battery, which is longer than standard 20700s.*
It also has kind of a cool feature where if you have a charged battery loaded you can use it as a portable power pack and charge USB devices like mobile phones, tablets, and the like using a USB cord.