The universal 510 thread makes the charger compatible with all 510 thread high capacity batteries. Ultra safe and smart, the 510 USB Charger has a built in over charge protection to ensure safely charge. The charger has an input DC 5V and output DC 4.2V, 420mA. Measuring at 1.8 inches by 0.8 inches by 0.5 inches, the 510 USB Charger is small in stature making it portable but don’t let the size fool you, this thing packs a powerful punch. Charging your Wulf batteries, the 510 USB Charger by Wulf Mods is the perfect addition to your collection.