The EGO USB charger is made specifically for Premium’s EGO batteries. The USB charger may be used in conjunction with Premium’s AC Adapter or just plugged directly into any USB port. To use simply, screw the EGO battery into the USB charger. The battery will then flash 3x to indicate it has been connected properly to the charger. The LED on the USB charger will show red while the battery is charging, then switch to green once the charge is complete.