The Metrix Slim Variable Voltage 510 battery is a great product for oil / e-liquid vapers. The Metrix Vape Pen features a 650mAh capacity and variable voltage settings. Adjust your settings based on the type of eliquid or oil you are vaping. The Vertex Vape Pen is designed for the beginner who is looking into vape products and wants something affordable, discreet and simple-to-use. This battery is one of the slimmest batteries on the market. Simply inhale to activate and a light will indicate that it is working. Perfect for pre-filled cartridges. Simply screw your cartridge onto the Metrix battery and you are ready to begin vaping.