The Efest Xsmart USB Battery Charger is a single bay 3.7V battery charger. The Xsmart charger is compatible with various battery types: 16340, 18350,18650,18490,18700, 14500, 17500. It features many safety features including automatic discharge current control for different types of batteries, auto cut-off, over-charge, over-voltage, short-circuit and reverse polarity protections. The Xsmart USB Battery Charger comes with USB charging cable, but also compatible with DC (12-24V) wall charging adapters.​​​​​​​