The Ooze Smart USB Charger MUST be used with all Ooze vaporizer batteries or the device's warranty will be voided. This charger protects the vape device by stopping the flow of energy from the outlet to the battery as soon as the device reaches a full charge. This eliminates the risk of the device overheating, and preserves battery cells which greatly extends the lifespan of the device. The charger has a small light on the front that will light up red while it is charging the vape and the battery light will be lit. Once the battery is done charging, the charger light turns green and the battery light shuts off. The charger plugs into a wall outlet adapter, and we strongly recommend only charging via a wall outlet. Do not charge your vape with your computer, gaming system, or any power source other than a wall outlet.