Basically the PODs (ultra portable systems) are something in the middle between vaping pen and the expensive box mod device. The structure is alike to the design of cartomizer, however it has more flexibility for liquid-volume and power.The essential distinction from the normal cartomizer of ultra portable POD system , POD includes cartridges as JUUL Replacement Pods, that have the coil, wick, e-liquid, basically all components you need.The Pod systems are much more powerful. Although the vape pen device battery caps out at approximately 180 mAh, ultra portable vaping devices can achieve of three hundred mAh.Remarkable fact that Pod systems are not expansive at all. Approximately at about 30 dollars you can buy fairly high quality ultra portable system, however not high quality Pods might cost approximately fifteen dollars.