The Streamlight AC Fast Charger is designed to put a full charge into your light in an hour or less without the hassle of having to take it out of the light to do it. When it's fully charged the charge automatically changes the current to a maintenance trickle charge, so your light will always be ready when you need it. The charger plugs into a standard US wall outlet via the 2-prong plug at the end of a long cord to give you placement options if your outlet isn't near where you need your light to live.