This replacement 900mAh sub-ohm variable voltage battery for your KandyPens Crystal Vaporizer is a large, powerful battery that provides a longer than usual battery life. You will enjoy longer vape sessions due to this. The battery has one button on the interface along with four LED lights. To turn the battery on and off, click the button five times quickly in a row. You also can choose your desired heating temperature using this button. The KandyPens Crystal Vaporizer battery gives you four voltage heating options: 2.6V, 3.0V, 3.6V and 4.2V. Choose a higher voltage for dense vapor and a lower voltage for tastier vapor! Be ready for a quick heat up and long sessions! The battery also has a sesh mode option best used with friends! You can charge the battery by using a micro USB charger in the port found on the side of the battery. The LED lights on the interface will also tell you how charged the battery is.