Vape pens are small, pen-sized vaporizers that can be easily put into a pocket or purse. Most of these vaping devices are hardly larger than regular ink pens, usually only slightly longer. Vape pens are usually driven by a small battery that screws onto a tank or atomizer that contains a heating coil system. The vaporizer pen is loaded up with nicotine-containing liquid. When vapers press the fire button, the battery engages the coil and then vapor happens.